Rain Garden Ideas: Designs Before and After

Rain garden ideas, each shown as a before and after picture: a downspout garden out in the lawn, a curbside strip, a dry creek, a rain barrel overflow, a garden that catches driveway runoff and one held by a berm on a slope. Each is a shallow bowl dug into the ground, fed by a rock inlet and planted thick. Below them: where to put one, how big and how deep, the drainage test, plants, mosquitoes and cost.

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Rain garden ideas, before and after

In each pair, the left image was generated by AI as a stand-in for an ordinary yard, and the right image is that same picture edited by AI from a written instruction. These are not photos of real customer homes. We made them with our own AI model, which is not one of the models you can pick in the landscape tool, so a render in the tool may look different. Our AI kept drawing raised flower beds or putting the garden against the house, so each pair here is the best of several runs. Most are shown just after rain and two are shown dry, and each caption says what the edit did not follow. The exact instructions are further down the page.

AI-generated example: the side of a two-storey beige house with a white downspout ending at a mulch strip, and a wide open lawn on the right — Downspout rain garden. Already in the before: the house, the downspout and the lawn. What followed the instruction: a round bowl dug into the lawn away from the wall, the grass sloping down into it, packed with grasses, blue iris, purple coneflowers, black-eyed Susans and red cardinal flowers. What it did not follow: the river cobbles stop at the foot of the downspout instead of running across the grass into the bowl, and it planted tall grasses against the house wall, which we asked it not to do, and it left more water showing than the small, mostly hidden pool we asked for. Shown just after rain: the water in the middle is meant to be there. A working rain garden drains within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch, so it is not a pond.

AI-edited version of the same image: a round sunken rain garden out in the lawn, packed with grasses, blue iris, purple coneflowers, black-eyed Susans and red cardinal flowers around a pool of rainwater, with river cobbles at the foot of the downspout — Downspout rain garden. Already in the before: the house, the downspout and the lawn. What followed the instruction: a round bowl dug into the lawn away from the wall, the grass sloping down into it, packed with grasses, blue iris, purple coneflowers, black-eyed Susans and red cardinal flowers. What it did not follow: the river cobbles stop at the foot of the downspout instead of running across the grass into the bowl, and it planted tall grasses against the house wall, which we asked it not to do, and it left more water showing than the small, mostly hidden pool we asked for. Shown just after rain: the water in the middle is meant to be there. A working rain garden drains within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch, so it is not a pond.

AI-generated example: a patchy grass strip between a concrete sidewalk and a street curb in front of a grey house with a lawn — Curbside strip. Already in the before: the house, the lawn, the sidewalk and the curb. What followed the instruction: the grass strip is dug down below the sidewalk and planted thick with grasses, blue iris, pink coneflowers, black-eyed Susans and red flowers, with a row of river cobbles along the curb. What it did not follow: we asked for a gap in the curb, lined with cobbles, where street water flows in, and it drew none, and the water runs the length of the strip where we asked for a small pool in the centre. Iowa's rain garden guide calls this strip right-of-way and says to check with your city or county before you build in it. Shown just after rain: the water in the middle is meant to be there. A working rain garden drains within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch, so it is not a pond.

AI-edited version of the same image: the strip between the sidewalk and the curb dug down and filled with grasses, blue iris, pink coneflowers, black-eyed Susans and red flowers, a line of rainwater down the middle and a row of river cobbles along the curb — Curbside strip. Already in the before: the house, the lawn, the sidewalk and the curb. What followed the instruction: the grass strip is dug down below the sidewalk and planted thick with grasses, blue iris, pink coneflowers, black-eyed Susans and red flowers, with a row of river cobbles along the curb. What it did not follow: we asked for a gap in the curb, lined with cobbles, where street water flows in, and it drew none, and the water runs the length of the strip where we asked for a small pool in the centre. Iowa's rain garden guide calls this strip right-of-way and says to check with your city or county before you build in it. Shown just after rain: the water in the middle is meant to be there. A working rain garden drains within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch, so it is not a pond.

AI-generated example: a backyard lawn sloping down from a grey house toward a wooden fence on a sunny day — Dry creek. Already in the before: the houses, the fence and the sloping lawn. What followed the instruction: a band of grey river cobbles with a few boulders winds down the slope, completely dry, and runs into an oval bowl dug into the lawn, its edge cut down below the grass and planted with grasses, blue iris, coneflowers, black-eyed Susans and red flowers. What it did not follow: we asked for plants over the whole floor of the bowl, and bare dark soil shows at the front; the cobbles also wrap along the left side of the bowl instead of ending where they meet it. Shown dry, the way it looks most days. After rain the water gathers in the bowl and soaks away within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch.

AI-edited version of the same image: a dry creek of grey river cobbles and boulders winding down the slope into an oval rain garden dug into the lawn, planted with grasses, blue iris, coneflowers, black-eyed Susans and red flowers, with dark soil showing at the front — Dry creek. Already in the before: the houses, the fence and the sloping lawn. What followed the instruction: a band of grey river cobbles with a few boulders winds down the slope, completely dry, and runs into an oval bowl dug into the lawn, its edge cut down below the grass and planted with grasses, blue iris, coneflowers, black-eyed Susans and red flowers. What it did not follow: we asked for plants over the whole floor of the bowl, and bare dark soil shows at the front; the cobbles also wrap along the left side of the bowl instead of ending where they meet it. Shown dry, the way it looks most days. After rain the water gathers in the bowl and soaks away within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch.

AI-generated example: the side of a cream stucco house with a white downspout down the wall and a wide open lawn stretching back to a grey wooden fence — Barrel and overflow. Already in the before: the house wall, the downspout, the lawn and the fence. What followed the instruction: the downspout runs into the top of a dark green rain barrel on two concrete blocks, and from the barrel's foot a channel of grey river cobbles curves away from the house, across the lawn, to an oval bowl planted with grasses, blue iris, coneflowers and black-eyed Susans, with plain grass between it and the house. What it did not follow: no overflow fitting is drawn at the top of the barrel; the cobbles start at its base, where a real overflow hose or pipe would run from near the top. Shown dry, the way it looks most days. After rain the water gathers in the bowl and soaks away within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch.

AI-edited version of the same image: a dark green rain barrel on two concrete blocks with the downspout running into its top, and a channel of grey river cobbles curving out across the lawn to an oval rain garden of grasses, blue iris, coneflowers and black-eyed Susans well away from the house — Barrel and overflow. Already in the before: the house wall, the downspout, the lawn and the fence. What followed the instruction: the downspout runs into the top of a dark green rain barrel on two concrete blocks, and from the barrel's foot a channel of grey river cobbles curves away from the house, across the lawn, to an oval bowl planted with grasses, blue iris, coneflowers and black-eyed Susans, with plain grass between it and the house. What it did not follow: no overflow fitting is drawn at the top of the barrel; the cobbles start at its base, where a real overflow hose or pipe would run from near the top. Shown dry, the way it looks most days. After rain the water gathers in the bowl and soaks away within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch.

AI-generated example: a modern white flat-roofed house with a concrete driveway along the left and a wide flat green lawn in front — Driveway runoff. Already in the before: the house, the driveway and the lawn. What followed the instruction: the driveway is left clear, a strip of river cobbles runs along its edge, and right beside it a long bowl dug into the lawn holds tall feathery grasses, blue iris, coneflowers, black-eyed Susans and red flowers. What it did not follow: we asked for the garden out in the middle of the lawn, and the water in it shows more than the small, mostly hidden pool we asked for. What it cannot show: which way the driveway slopes. For this to work in your yard the concrete has to drain toward the cobbles. Shown just after rain: the water in the middle is meant to be there. A working rain garden drains within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch, so it is not a pond.

AI-edited version of the same image: a strip of river cobbles along the edge of the driveway and, beside it, a long sunken rain garden of tall feathery grasses, blue iris, coneflowers, black-eyed Susans and red flowers around a pool of rainwater — Driveway runoff. Already in the before: the house, the driveway and the lawn. What followed the instruction: the driveway is left clear, a strip of river cobbles runs along its edge, and right beside it a long bowl dug into the lawn holds tall feathery grasses, blue iris, coneflowers, black-eyed Susans and red flowers. What it did not follow: we asked for the garden out in the middle of the lawn, and the water in it shows more than the small, mostly hidden pool we asked for. What it cannot show: which way the driveway slopes. For this to work in your yard the concrete has to drain toward the cobbles. Shown just after rain: the water in the middle is meant to be there. A working rain garden drains within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch, so it is not a pond.

AI-generated example: a backyard lawn on a gentle slope with a grey wooden fence and a few young trees — Berm on a slope. Already in the before: the fence, the young trees and the sloping lawn. What followed the instruction: a curved bowl across the slope with a grass-covered berm wrapped around its downhill side to hold the water in, filled with grasses, blue iris, coneflowers and black-eyed Susans. What it did not follow: the berm is taller and steeper than the low, gentle swell we asked for, and the cobble channel runs along the fence rather than clearly into the bowl, and more water shows than we asked for. Shown just after rain: the water in the middle is meant to be there. A working rain garden drains within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch, so it is not a pond.

AI-edited version of the same image: a curved rain garden across the slope, wrapped on its downhill side by a grassy berm, filled with grasses, blue iris, coneflowers and black-eyed Susans around a pool of rainwater, with river cobbles along the fence — Berm on a slope. Already in the before: the fence, the young trees and the sloping lawn. What followed the instruction: a curved bowl across the slope with a grass-covered berm wrapped around its downhill side to hold the water in, filled with grasses, blue iris, coneflowers and black-eyed Susans. What it did not follow: the berm is taller and steeper than the low, gentle swell we asked for, and the cobble channel runs along the fence rather than clearly into the bowl, and more water shows than we asked for. Shown just after rain: the water in the middle is meant to be there. A working rain garden drains within a day or two (Penn State says 12 to 24 hours, never more than 48), long before mosquitoes can hatch, so it is not a pond.

Where to put a rain garden

A rain garden is a shallow, planted dip that catches water from a roof, driveway or lawn and lets it soak in, usually within a day. It is not a pond or a water garden (UConn). Where you put it matters more than how it looks.

How far from a septic system, a well and water underground, by source. They disagree, so check your local health department.
Source	Septic	Well	Water table or bedrock
Wisconsin DNR (2018)	5 ft	8 ft	1 ft above
NC Cooperative Extension	25 ft from the drain field	10 ft	–
Clemson (2016)	25 ft from the drain field	–	No shallower than 18 in
UNL Extension	25 ft	25 ft	2 ft below
UF/IFAS	25 ft	25 ft	–
UConn	Not over it	–	Bedrock: not closer than 2 ft
Iowa (2021)	100 ft, downslope	100 ft private, 200 ft public	–

Away from the house: At least 10 feet from the house, so the water does not seep into the foundation (Wisconsin DNR, Penn State, UNL, Clemson, UF/IFAS). Iowa's guide prefers 30 to 40 feet from a basement. Rutgers allows 2 feet for a house with no basement.
Downhill, not uphill: Put it where water already flows away from the house, not uphill of the house, a septic system or a well (NC Cooperative Extension). Don't send the overflow back toward the foundation (UConn).
Not where water already ponds: Wisconsin's 2003 manual says it is tempting, then: "Don't!" Wet patches show where water soaks in slowly, and a rain garden needs soil that soaks it in.
Not under a big tree: Wisconsin's 2003 manual says roots make it hard to dig and the extra water could damage the tree; UNL says not directly beneath a tree canopy.
On a gentle slope: Under about 12 percent is best (Wisconsin DNR, UNL); Penn State calls over 10 percent not ideal. On steeper ground, Wisconsin's 2018 guide suggests terraces or a landscape professional.
Buried lines: Call 811 before you dig (Wisconsin DNR, UF/IFAS). UConn warns that 811 will not locate small lines such as wires to outdoor lights, and Iowa adds private lines such as electric dog fences.
Sun: NC Cooperative Extension says partial to full sun, at least 4 hours a day. Clemson says shady rain gardens work too, with shade plants.
Walk it in the rain: Penn State's tip: walk the yard during a storm and watch where the water goes.

How big to make a rain garden

Size comes from the area that drains into the garden and from how fast your soil drains. First find the drainage area: for a downspout, the part of the roof that drains to it. Wisconsin's example is a 60 by 40 foot roof (2,400 sq ft) with a downspout taking a quarter of it, so 600 sq ft.

Then multiply by the sizing factor from the table. Wisconsin's example: 600 sq ft, silty soil, 6 inches deep and under 30 feet from the downspout, so 600 × 0.30 = 180 sq ft. At 10 feet wide that is 18 feet long.

Sizing factors from Wisconsin DNR's 2018 guide. Multiply the drainage area by the factor to get the garden area. Soil types by how fast they drain (inches per hour).
Depth / distance	Sandy (over 1.0)	Silty (0.41–1.0)	Clayey (0.15–0.40)
3–5 in deep, under 30 ft from downspout	0.17	0.35	0.44
6–7 in deep, under 30 ft	0.13	0.30	0.35
8 in deep, under 30 ft	0.11	0.23	0.25
Over 30 ft from downspout, any depth	0.03	0.08	0.10

Simpler rules give other answers: Penn State says 10 to 20 percent of the hard surface draining to it. UConn says a typical home rain garden is 50 to 100 sq ft; Wisconsin's 2003 manual says 100 to 300 sq ft. If the number is too big for your yard, Wisconsin's 2003 manual says a garden up to 30 percent smaller still controls almost 90 percent of the runoff, and bigger is fine too.

Shape: about twice as long as it is wide, with the long side across the slope so water spreads along it (Wisconsin DNR 2003). Crescent, kidney and teardrop shapes all work.

How deep to dig a rain garden

Most guides say 4 to 8 inches of ponding depth (Wisconsin DNR 2003, UNL, UF/IFAS); Wisconsin's 2018 guide says 3 to 8. Deeper holds water too long and looks like a hole; UF/IFAS says anything deeper could become a breeding ground for mosquitoes. The bottom should be level, so on a slope you dig more on the uphill side and use the soil to build a low berm on the downhill side.

Ponding depth by the slope of the ground, from Wisconsin DNR's 2003 manual. Slope = drop in height ÷ distance × 100.
Slope	Depth
Under 4%	3 to 5 in
5 to 7%	6 to 7 in
8 to 12%	About 8 in
Over 12%	Pick another spot (2003) or ask a professional (2018)

That is the depth of the water, not of the hole. NC State's guide says to dig the ponding depth plus 3 inches for mulch.

Test how fast your soil drains

Dig a test hole where the garden will go, fill it with water, and time it. The guides use different holes and pass lines:

Wisconsin DNR (2003): Dig a hole 6 to 12 inches deep, fill it with water and let it soak for an hour, then refill it and measure the water with a ruler. If it drops more than half an inch in one hour, the site should be suitable. Half an inch or less: pick another site.
NC State (NC WRRI): Dig a hole 24 inches deep and 12 inches wide and fill it with water. If it takes more than 36 hours to drain, the site is not right for a rain garden. If you hit groundwater while digging, it is not right either.
Iowa (2021): Over half an inch per hour works for a basic rain garden.
Clemson (2016): A drop of 1 to 6 inches in the first hour is ideal. If the hole has not drained in 24 hours, Clemson suggests a bog garden or backyard wetland instead.
UNL: Soil should take in at least a quarter inch per hour.

Soil, mulch and where the water goes in and out

Soil: Wisconsin's 2018 guide works about 2 inches of compost into the top 4 to 6 inches. NC State says at least 25 percent amendment. Clemson's mix is 50 to 60 percent sand, 20 to 30 percent topsoil and 20 to 30 percent compost.
Mulch: Shredded hardwood: 2 to 3 inches (Penn State), about 3 inches double-shredded (Wisconsin DNR 2003), 3 to 4 inches (Clemson). Penn State says to avoid dyed mulch and too much mulch, which can float away in storms. Clemson suggests cedar over cypress and avoids pine straw and pine bark.
Inlet: Line where the water comes in with rock so it does not wash out the bed: NC State says you can use rocks to channel water from the downspout, and Iowa uses 3 to 4 inch rock at the inlet and outlet. UConn says stones there slow the water down.
Berm and overflow: On a slope, a low berm on the downhill side holds the water level. Big storms will overflow it, so plan where: NC Cooperative Extension makes a 1-foot-wide low spot (a weir) in the berm, and Clemson reinforces that dip with river rock. Wisconsin's 2018 guide stabilizes the opening with gravel.

Plants for a rain garden

Rain garden plants handle both wet spells and dry ones (Clemson). Most guides use native perennials, grasses and sedges. Wisconsin's 2018 guide says to plant each kind in groups of 3 to 7, mix bloom times, heights and textures, and include sedges and grasses with the flowers. Wisconsin's 2003 manual sets plants 1 foot apart in a grid; Iowa uses 12 inches.

UNL says to avoid trees in most cases. For shade, Clemson notes shady rain gardens work with shade plants.

Ask your local extension office for a native plant list for your area; the right plants differ a lot between, say, Wisconsin and Florida.

Mosquitoes and how long water should stand

A working rain garden does not breed mosquitoes. Mosquitoes need 7 to 12 days of standing water to lay and hatch eggs (Wisconsin DNR); Clemson says 7 to 10 days, NC Cooperative Extension about a week. A rain garden should be dry long before that.

How long water should stand after a storm, by source.
Source	Drain time
UConn	About 6 hours is typical
Iowa (2021)	12 hours or less: rain in the afternoon, no standing water by morning
Wisconsin DNR (2003)	Not more than a day
Penn State	12 to 24 hours, never more than 48

If water stands longer, the soil is too slow or packed down; Wisconsin's 2003 manual suggests leaving a temporary gap in the berm for the first year or two until the garden drains in under a day.

Looking after a rain garden

First weeks: Water new plants for the first few weeks until they settle in (Wisconsin DNR 2003).
First two seasons: Weed regularly; weeding time drops as the plants fill in (Wisconsin DNR 2003, Penn State).
Each spring: Leave stems and seed heads over winter for birds. When new growth is 4 to 6 inches tall, cut back the old stems (Wisconsin DNR 2003); the 2018 guide cuts them to 6 to 8 inches.
Mulch: Top up while the plants fill in. Penn State says an established garden does not need mulch every year, because the plants shade the soil.
Winter: Don't pile shoveled snow on it: Penn State says snow piles carry road salt, sand and oil that can damage plants and soil.

What a rain garden costs

Cost per square foot, by source and year.
Source	Cost
Wisconsin DNR (2003)	$3 to $5 doing it yourself with bought prairie plants; $12 to $15 with a landscaper
Rutgers	$3 to $5
Iowa (2021 materials)	$4 to $10 for a basic do-it-yourself garden under 400 sq ft
UConn	Plants alone about $1 to $2

So a 180 sq ft garden like Wisconsin's example comes to roughly $540 to $1,800 doing it yourself, more with a landscaper. Plants shared by neighbors cut that a lot.

How to try a rain garden on a photo of your yard

Take a photo of the spot from where you would normally see it, in daylight, with the downspout or the low area in frame.
Open the landscape tool, choose Custom, and paste one of the instructions below into the Custom Design Requirements box.
Change the plants, the shape and what must stay, then generate.
If it misses something, as every one of our examples did, reword that part and run it again. Our AI kept putting gardens against the house, so say plainly where it must not go.

The picture shows the look and roughly where the garden would sit. It does not measure slope, depth or drainage, so plan those with the tables above.

Rain garden instructions to paste into Custom mode

These are the exact instructions we used for the examples above, in the same order. In the landscape tool, choose Custom, paste one into the Custom Design Requirements box, then upload a photo of your yard. Swap in your own plants, shape and what must stay.

Leave the grass along the house wall plain, nothing planted against the house. In the foreground, a wide, clearly visible channel of rounded grey river cobbles starts at the bottom of the white downspout and runs straight out across the green lawn toward the right, about fifteen feet, and spills down into a large oval rain garden out in the open lawn on the right side of the picture. The rain garden is a shallow hollow dug down into the lawn, like a wide shallow bowl in the ground: the grass slopes gently DOWN into it, so the plants grow from a floor clearly lower than the lawn. No raised edge, no wall. It has just rained: a small shallow pool of clear water shows only in the very centre of the hollow, mostly hidden by plants. The plants fill almost the whole hollow, dense and overflowing: big clumps of tall feathery switchgrass, sedges, tall blue flag iris, masses of purple coneflowers, golden black-eyed Susans, pink swamp milkweed and red cardinal flowers in full bloom, magazine-quality garden photo in golden afternoon light. Keep the house, the camera angle and everything else exactly the same. No people.
Turn the grass strip between the sidewalk and the curb into a long rain garden. Its floor is dug down below the sidewalk and the top of the curb, with the soil sloping down from both edges, so it is clearly lower than the sidewalk. Where water comes in from the street there is a short gap in the curb lined with rounded river cobbles. It has just rained: a small shallow pool of clear water shows only in the very centre of the strip, mostly hidden by plants. The plants fill almost the whole strip, dense and overflowing: big clumps of knee-high feathery grasses, sedges, tall blue flag iris, masses of purple coneflowers, golden black-eyed Susans, pink swamp milkweed and red cardinal flowers in full bloom, magazine-quality garden photo in golden afternoon light. Keep the house, the camera angle and everything else exactly the same. No people.
Add a dry creek bed: a winding band of rounded grey river cobbles with a few larger boulders along its edges, about two feet wide, set into the lawn. It starts near the house at the top of the slope and winds down across the grass to a large oval rain garden in the low foreground of the picture. The creek is completely DRY: only dry pale grey stones, no water in it at all, no stream, no waterfall. The cobbles end where the creek meets the rain garden. The rain garden: It is a shallow hollow dug down into the lawn, like a wide shallow bowl in the ground: the grass slopes gently DOWN into it from every side, so the plants grow from a floor clearly lower than the lawn around it. There is no raised edge, no wall, no curb and no ring of stones around it; plain grass meets the plants directly. Plants cover the entire floor of the hollow from edge to edge, so thick that no soil, no water and no open centre can be seen: big clumps of tall feathery switchgrass, sedges, tall blue flag iris, masses of purple coneflowers, golden black-eyed Susans, pink swamp milkweed and red cardinal flowers in full bloom. No pond, no pool, no water anywhere. Magazine-quality garden photo in golden afternoon light. Keep the house, the fence, the camera angle and everything else exactly the same. No people.
Add a dark green plastic rain barrel, about waist high, standing on two grey concrete blocks against the house wall. The white downspout is cut short and ends directly into the open top of the barrel, so the roof water clearly goes into the barrel. The grass along the house wall stays plain lawn; nothing else is planted or built against the house. From the foot of the barrel a narrow channel of rounded grey river cobbles turns away from the house at once and runs diagonally out across the open lawn toward the fence at the back, never along the wall, about twenty feet long, and ends at a large oval rain garden in the middle of the lawn, halfway to the fence, with a wide stretch of plain grass between the house and the garden. The rain garden: It is a shallow hollow dug down into the lawn, like a wide shallow bowl in the ground: the grass slopes gently DOWN into it from every side, so the plants grow from a floor clearly lower than the lawn around it. There is no raised edge, no wall, no curb and no ring of stones around it; plain grass meets the plants directly. Plants cover the entire floor of the hollow from edge to edge, so thick that no soil, no water and no open centre can be seen: big clumps of tall feathery switchgrass, sedges, tall blue flag iris, masses of purple coneflowers, golden black-eyed Susans, pink swamp milkweed and red cardinal flowers in full bloom. No pond, no pool, no water anywhere. Magazine-quality garden photo in golden afternoon light. Keep the house, the fence, the camera angle and everything else exactly the same. No people.
Keep the concrete driveway on the left completely clear, dry and unchanged. Out in the middle of the front lawn add one long, gently curved rain garden. A strip of rounded grey river cobbles runs from the edge of the driveway across the grass and spills down into the rain garden. The rain garden is a shallow hollow dug down into the lawn, like a wide shallow bowl in the ground: the grass slopes gently DOWN into it, so the plants grow from a floor clearly lower than the lawn. No raised edge, no wall. It has just rained: a small shallow pool of clear water shows only in the very centre of the hollow, mostly hidden by plants. The plants fill almost the whole hollow, dense and overflowing: big clumps of tall feathery switchgrass, sedges, tall blue flag iris, masses of purple coneflowers, golden black-eyed Susans, pink swamp milkweed and red cardinal flowers in full bloom, magazine-quality garden photo in golden afternoon light. Keep the house, the camera angle and everything else exactly the same. No people.
Add a large curved rain garden across the slope. A channel of rounded grey river cobbles comes down the slope from the upper left and spills down into it. The rain garden is a shallow hollow dug down into the lawn, like a wide shallow bowl in the ground: the grass slopes gently DOWN into it from every side, so the plants grow from a floor that is clearly lower than the lawn around it. There is no raised edge, no wall and no curb around it; the lawn simply dips down into it. On the downhill side only, the lawn rises into a low, soft, gently rounded grassy mound of earth that holds the water in. It has just rained: a small shallow pool of clear water shows only in the very centre of the hollow, mostly hidden by plants, while the lawn around it is higher and dry. The plants fill almost the whole hollow, dense and overflowing like a mature English cottage border: big clumps of tall feathery switchgrass, soft green sedges, tall blue flag iris, masses of purple coneflowers, golden black-eyed Susans, pink swamp milkweed and red cardinal flowers in full bloom, almost no mulch visible, magazine-quality garden photo in golden afternoon light. Keep the house, the camera angle and everything else exactly the same. No people.

Try a rain garden on my photo

Rain garden questions

How far from the house should a rain garden be?

At least 10 feet, so water does not seep into the foundation (Wisconsin DNR, Penn State, UNL, Clemson, UF/IFAS). Iowa prefers 30 to 40 feet from a basement. Rutgers allows 2 feet for a house without a basement.

How big should a rain garden be?

Multiply the area that drains to it by a sizing factor for your soil and depth. In Wisconsin's example, 600 sq ft of roof on silty soil at 6 inches deep gives 600 × 0.30 = 180 sq ft. Penn State's simpler rule is 10 to 20 percent of the hard surface draining to it.

How deep should a rain garden be?

Usually 4 to 8 inches of ponding depth (Wisconsin DNR, UNL, UF/IFAS): about 3 to 5 inches on flat ground, up to about 8 inches on an 8 to 12 percent slope. Dig about 3 inches more for mulch.

Do rain gardens attract mosquitoes?

Not when they drain properly. Mosquitoes need 7 to 12 days of standing water to lay and hatch eggs (Wisconsin DNR), and a rain garden should drain in about a day or less.

Can I put a rain garden where water already pools?

Usually not. Wisconsin's 2003 manual says wet patches show where water soaks in slowly. Do a drainage test first; if the hole has not drained in 24 hours, Clemson suggests a bog garden instead.

What should I plant in a rain garden?

Native perennials, grasses and sedges that handle wet and dry spells, in groups of 3 to 7 (Wisconsin DNR). Use shade plants such as ferns, hostas and sedges in shade. Ask your local extension office for a native plant list.

How much does a rain garden cost?

About $3 to $5 per square foot if you do it yourself (Wisconsin DNR, Rutgers), $4 to $10 for materials in Iowa's 2021 guide, and $12 to $15 with a landscaper (Wisconsin DNR, 2003).

Can I see a rain garden on a photo of my own yard?

Yes. Upload a photo to the landscape tool, choose Custom, and describe the garden: its shape, plants, where it sits and what must stay. The result is a picture for planning, not a measured plan.

Is the rain garden tool free?

You need an account, and it is free: 1 free render with a free account (sign in with Google or an email code). More renders come with a paid plan.

Sources for the rain garden facts

More garden and yard ideas

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For more, browse all of our landscaping ideas, sorted into front yards, backyards, patios, gardens, pools, styles and regions.