Catch Basin Installation: How to Install a Yard Drain

By the Landscape Drainage Proz team, an authorized NDS dealer. Specs from NDS catalogs, technical specifications and installation details. Last updated September 24, 2026.

A catch basin fixes a puddle that keeps coming back. It is a plastic box buried at the low spot, with a grate at ground level. Water drops through the grate, dirt settles in the bottom, and a pipe carries the water somewhere it can do no harm.

This guide covers where to put a catch basin, how deep to dig, how to connect the pipe and how to finish it so it keeps draining. The specs come from NDS, the manufacturer of the 9 in. and 12 in. catch basin kits we sell.

What a Catch Basin Does

Water runs to the lowest point it can reach. If that point is a lawn, a patio or the ground next to your foundation, it sits there. A catch basin gives the water a way out at that exact spot.

• Grate: lets water in and keeps out leaves, mulch and feet.
• Sump: the space below the outlet. Grit and debris settle here instead of clogging the pipe.
• Outlet: a side opening fitted with an adapter that connects to your drain pipe.

A catch basin handles water that collects at one point. If water sheets across a driveway or patio along a whole edge, a channel drain is the better fit. If the ground itself stays soggy, you need a French drain to pull water out of the soil. Many yards use a basin and one of these together.

9 in. vs. 12 in. Catch Basin: Which Size?

NDS makes square catch basins in 9, 12, 18 and 24 in. sizes. The 9 in. and 12 in. kits cover most homes and small commercial sites. Both kits come with the basin, a grate, screws, a #1243 locking outlet, a #1245 offset outlet and an outlet plug.

Grate flows are NDS figures for the black, green, gray and sand plastic square grates. Pick the 9 in. basin for a single downspout, a planter bed or a narrow side yard. Pick the 12 in. basin for a big low spot in a lawn, a driveway or patio edge, or anywhere two pipes meet.

Where to Put a Catch Basin

Before you dig, watch where water collects during a heavy rain, or run a hose and see where it goes. Good spots:

• The lowest point of a lawn depression that stays wet after storms
• At the base of a downspout
• At the bottom of a slope, before water reaches a patio, walkway or the house
• Along a driveway or patio edge where runoff pools

Then plan where the water goes. The basin only collects it; the pipe has to carry it to one of these:

• Daylight: a spot lower than the basin, such as a slope or a ditch, finished with a pop-up emitter.
• A dry well: when there is no lower ground, an NDS Flo-Well dry well stores the water and lets it soak in. See our dry well installation guide.
• A storm drain or curb: only where your town allows it. Many towns restrict these connections or require a permit.

The pipe needs a steady downhill fall the whole way. NDS recommends at least 1% slope, which is 1 ft of drop per 100 ft of pipe (about 1/8 in. per foot). If the outlet is not lower than the basin by at least that much, move the outlet or use a dry well.

How Deep Does a Catch Basin Need to Be?

The hole needs to fit the basin plus a 4 to 6 in. bed of 3/4 in. gravel under it. NDS shows that gravel bed in its installation details so water in the sump can drain out instead of standing.

The depth that matters for the pipe is the invert: the distance from the top of the basin to the bottom of the outlet opening. Your pipe starts at that depth and falls from there.

Measurements are from the top of the basin, from the NDS catch basin invert table. The #1245 offset outlet in each kit can be turned to set the pipe a little higher or lower. Need the pipe deeper, for example to clear a walkway or reach a distant outlet? Stack a 6 in. riser on the basin (#916 for 9 in., #1216 for 12 in.). Risers can be cut to the exact height.

Materials and Tools

• NDS catch basin kit (basin, grate, screws, outlet adapters, plug)
• 3 in. or 4 in. drain pipe: corrugated, sewer and drain, triple-wall or Schedule 40
• 3/4 in. crushed stone or gravel for the base
• A pop-up emitter, dry well or other outlet for the far end of the pipe
• Shovel and trenching shovel, tape measure, 4 ft level, line level or string line, hand tamper
• Drill with a 1/8 in. bit (optional weep holes)
• Marking paint and stakes

How to Install a Catch Basin, Step by Step

1. Call 811 and check local rules. Call 811 a few days before you dig so buried utility lines get marked. Ask your town whether you need a permit and where you may discharge stormwater.
2. Mark the basin and the pipe route. Paint the basin footprint a little larger than the basin, then the trench path to your outlet. Check with a level or string line that the route can fall at least 1% the whole way.
3. Dig the hole and the trench. Dig the hole about 6 in. wider than the basin on each side, and deep enough for the basin plus 4 to 6 in. of gravel. Dig the trench from the basin to the outlet, sloping downhill the whole way. Keep the topsoil or sod to one side for finishing.
4. Lay the gravel base. Spread 4 to 6 in. of 3/4 in. gravel in the hole and tamp it level. The basin should sit flat and not rock.
5. Prepare the basin. Snap the #1243 locking outlet (or the #1245 offset outlet) into the side opening that faces the pipe run. Put the plug in the opening you are not using. If you want the sump to drain between storms, drill four 1/8 in. weep holes in the bottom corners, as the NDS detail shows.
6. Set the basin. Lower it onto the gravel. Check that it is level both ways and that the top sits about 1/8 in. below the finished ground once the grate is on. Add or remove gravel until it does.
7. Connect and lay the pipe. Push the pipe into the outlet adapter; the locking outlet snaps onto most corrugated pipe. Lay the pipe in the trench, checking the fall every few feet, and connect it to the pop-up emitter, dry well or other outlet.
8. Test it before you backfill. Pour a few buckets of water or run a hose into the basin. Water should leave through the pipe and come out at the far end without backing up.
9. Backfill and finish. Backfill around the basin and over the pipe in layers, tamping gently as you go so nothing shifts. Grade the soil so it slopes toward the grate from all sides, then replace the sod.
10. Attach the grate. Set the grate and fasten it with the screw provided so it cannot be kicked or mowed loose.

Download the NDS 9 in. catch basin landscape installation detail (PDF) or the 12 in. catch basin landscape installation detail (PDF) for the drawings.

Catch Basins in Driveways and Patios

A catch basin in pavement needs more support than one in a lawn. NDS shows a concrete collar around the basin in its pedestrian and vehicular traffic installation detail (PDF):

In traffic areas, NDS recesses the grate 1/4 in. below the pavement instead of 1/8 in. The plastic square grates in our kits are rated Class B, so they suit driveways and parking pads with cars and light trucks. For trucks, forklifts or anything heavier, NDS makes cast iron and galvanized steel grates; ask us for a quote.

Common Mistakes to Avoid

• No downhill fall. If any stretch of the pipe runs flat or uphill, water sits in it and the basin backs up. Check the slope as you lay the pipe, not after.
• Grate set too high. A grate that sits above the ground sheds water around it. Set it slightly below grade.
• Open side opening. An unplugged second opening lets soil wash into the basin. Use the plug.
• No plan for the water. Dumping it near the house or onto a neighbor's yard just moves the problem. Decide on the outlet before you dig.
• Skipping the gravel base. A basin set on loose soil settles and tilts. The grate then sits out of level and the outlet can pull away from the pipe.
• Using a basin for a soggy lawn. A basin catches surface water. If the soil stays saturated, add a French drain.

Keeping a Catch Basin Working

Lift the grate a few times a year, and after big storms or leaf drop, and scoop out what has settled in the sump. If water drains slowly, flush the pipe with a hose from the basin end. A 9 in. NDS catch basin filter (#900FF) is available if a lot of fine sediment reaches the basin.

Which Catch Basin Kit Should I Buy?

• NDS 9 in. catch basin kit, 4-pack: downspouts, planter beds, side yards and small patios. $214.50 for four kits.
• NDS 12 in. catch basin kit, 4-pack: large low spots, driveway and patio edges, and pipe junctions. $255 for four kits.
• NDS Pro Series channel drain: when water runs across a whole driveway or patio edge instead of pooling in one spot.
• NDS Flo-Well dry well and EZ-Flow gravel-free French drain: where the water goes when there is no lower outlet.

More drainage guides: channel drain installation · French drain installation · dry well installation. Buying for a town, school or contractor? See municipal and contractor accounts.