How to Install a Channel Drain in a Driveway, Patio or Pavers

Here’s how to install a channel drain: cut a trench across the path of the water, set the channel sections in a concrete surround with the grate a hair below the surface, and pipe one end to an outlet lower than the drain. Two decisions made before any digging decide whether it works: where the outlet goes and which load class the grate needs.

The numbers below come from NDS and ACO, two big channel drain makers. They differ a little, so follow the sheet for the product you buy.

Plan the outlet, fall and load class first

Where the water goes

A channel drain only collects water. Its outlet pipe has to carry that water downhill to a daylight spot, a dry well, or a storm sewer where your town allows the tie-in. As NDS puts it for its pop-up emitter systems, the outlet must sit lower than where water enters, or the system won’t drain.

If you aren’t sure the drain is the right fix, our guide to water running into your garage covers checking the roof water and apron first. The outlet line’s trenching, solid pipe and emitter work is in how to bury a downspout, and a dry well is the usual answer when there’s no lower ground.

Water pooling at one low spot in the lawn instead of crossing pavement? A catch basin may fit better; see catch basin vs French drain. If the roof is the source, start with how far downspouts should extend. All our wet-yard fixes are in the yard drainage guide.

How much fall the run needs

NDS calls for a minimum 1 percent slope, roughly 1 inch of drop every 8 feet, and says 2 percent works better on most homes. Its driveway drainage instructions apply the same 1 percent to the pipe trenches running away from the house.

A neutral, constant-depth channel follows the paving, so it only has fall where the surface slopes along the drain line. Across level paving, use a pre-sloped system: numbered sections with the fall molded in, set in a trench that deepens toward the outlet.

Which load class the grate needs

Channel drains are rated under EN 1433, a European standard whose classes are named for their test load in kilonewtons. The class matters here because it sets how much concrete goes around the channel.

For a house, ACO recommends at least B 125 on driveways and C 250 if heavier vehicles may use it. Hauraton puts vans, light trucks and campers in C 250. NDS calls Class C suitable for most residential driveways for its BG-FILCOTEN trench drain and keeps its pedestrian-grate Micro channels to patios and sidewalks. Buy for the heaviest vehicle that will ever cross the drain.

How to install a channel drain in a concrete driveway

These steps follow ACO’s site installation manual and the NDS guide. Contact 811 a few business days ahead (your state’s exact notice rule is in our 811 dig laws guide), confirm every utility has responded before you dig, and dig around the marks, not on them. We call before every dig, including short outlet trenches.

1. Mark and cut. Snap the line where the water crosses, usually just before the garage door, and run the drain the full width of the paving so water can’t slip around an end. Saw-cut clean, straight edges through the concrete or asphalt.
2. Dig the trench. Make it as wide as the channel plus the concrete surround on both sides, and as deep as the channel plus the surround underneath (for driveways, NDS calls for the drain body plus a 4-inch concrete base). Remove loose material and compact a crushed stone base.
3. Set a line at finished grade. Run a string line or laser at the finished surface for the full length. Set the outlet section or catch basin first and connect and seal the outlet pipe, then work upstream with the molded arrows pointing toward the outlet.
4. Set the height. ACO’s patty method sets each section on two pads of low-slump concrete, then packs more concrete over the keys on the channel sides so it can’t float during the pour. Keep concrete out of the joints between sections.
5. Brace and cover. Put the grates, or snug-cut 3/4-inch plywood, in the grate seat so wet concrete can’t squeeze the channel walls. Wrap the grates in plastic or tape.
6. Pour the surround. Use 4,000 psi concrete and place it evenly on both sides so the channel doesn’t shift. Trowel the edges with a slight slope down to the channel.
7. Joint it. Line up crosswise slab joints with channel joints, or ACO says to cut through the channel there and seal it with flexible sealant. Put an isolation joint between the new surround and the old slab.
8. Cure and test. ACO says to wait 24 hours before removing the bracing. Then fit the grates and run a hose into the drain to check that water reaches the outlet.

ACO’s minimum surround depends on channel width and load class. ACO says to at least match the slab thickness, go bigger on poor ground and get engineering advice on rebar.

Channel width	Class A	Class B	Class C	Class D
4 in.	4 in.	4 in.	6 in.	6 in.
8 in.	4 in.	4 in.	6 in.	8 in.
12 in.	6 in.	6 in.	8 in.	12 in.

Under traffic, the concrete surround does much of the work of carrying the load, which is why ACO sizes it by load class. Give the new concrete its full cure before cars cross it; our guide on when you can drive on new concrete has the timing.

How to install a channel drain in pavers or a patio

ACO’s manual says pavers next to the channel must be fully bonded to the concrete haunch, with the rest of the field bedded on compacted sand as usual. Above Class B, it calls for a full concrete surround.

Set the pavers about 1/8 inch above the grate so water runs in. Lay out the field so the cuts land away from the drain, not as slivers against it.

On a patio, the surface has to pitch toward the drain or the drain does nothing. The fall away from the house is covered in our patio slope guide. A pedestrian Class A channel is fine on a patio, walk or pool deck, but not where a car will ever cross.

For asphalt, ACO calls for a full concrete surround above Class C. Protect the channel while the asphalt is rolled and finish the asphalt about 1/8 inch above the grate.

Mistakes that make channel drains fail

• No real outlet. A drain piped to ground that’s level with it, or higher, fills and overflows.
• Too light a grate. A pedestrian channel across a driveway isn’t built for tires.
• A neutral channel across level paving. With no fall, water and grit sit in the trough; use pre-sloped sections there.
• Loose pavers at the edge. ACO requires bonding the pavers beside the channel because loose ones can shift and damage it.

Maintenance and winter

NDS suggests checking grates quarterly, especially in fall when leaves pile up, and checking outlet connections once a year. ACO says to inspect at least annually: lift the grates, clear debris and flush the channel.

In cold climates, the outlet pipe needs continuous fall to its end so it drains empty after every storm. A sag holds water that freezes, and the next thaw backs up at the drain.

DIY or hire a pro

A short patio or walkway run with a pedestrian channel is a fair DIY job; NDS says experienced homeowners can handle straightforward installs.

Hire out driveway work: saw-cutting the slab, pouring a structural surround and trenching a long outlet line with steady fall. NDS also points to pros for tie-ins to existing drainage, and a storm sewer connection may need your township’s approval. If you’d like the whole thing laid out first, our backyard drainage plans show the drain, the pipe route, the fall and the outlet on your lot to scale.

Frequently Asked Questions

How deep should a channel drain be?

Deep enough for the channel body plus the concrete under it. NDS calls for a 4-inch concrete base under a driveway drain, and ACO’s minimum for a 4-inch channel is 4 inches at Classes A and B and 6 inches at Class C, so the trench is the channel depth plus 4 to 6 inches.

Does a channel drain need to be sloped?

Yes. NDS calls for at least 1 percent fall, about 1 inch every 8 feet, and prefers 2 percent. A neutral channel gets its fall from the paving it sits in; across level paving, use a pre-sloped system with the fall molded in.

Can you install a channel drain without concrete?

Not where cars cross it. NDS has the concrete completely encase a driveway channel, and ACO calls for a full concrete surround in paver installations above Class B. For a pedestrian patio drain, follow that product’s instructions.

Can you add a channel drain to an existing driveway?

Yes. Saw-cut a strip across the slab, dig out for the channel and its concrete surround, and pour new concrete with an isolation joint to the old slab. NDS notes that drains installed during new construction or a major renovation usually perform better long term than retrofits, so plan one in if you’re repaving anyway.

Sources: NDS, How to Install a Trench or Channel Drain; NDS, Water on Driveway Installation Instructions (High Capacity); ACO, Site Installation Manual: Polymer Concrete Trench Drain Systems (2021); ACO, Drainage Load Class; Hauraton, Load Classes for Drainage Channels (EN 1433); 811 Before You Dig

Written and reviewed by Thayne Muthler, owner of Muthler Landscaping & Construction (PA HIC #PA212584). How we check facts: editorial policy.