Curb Drain Outlet in Roseville, CA

A curb drain outlet is the last piece of a yard drain line: a hole cored through the street curb with a fitting set in it, so piped water leaves your property at the gutter. It suits Roseville homeowners whose lot slopes toward the street and whose downspouts, catch basins or French drains need somewhere legal to send their water.

What a curb drain outlet does and when it makes sense

Most yard drainage problems come down to one question: where does the water go once you have collected it? A curb drain outlet answers that by sending it to the street gutter, which already carries stormwater to the city system. It is one option within our wider yard drainage work, and it is often the simplest and most dependable one when the ground allows it.

It makes sense when the front of the lot sits higher than the gutter, when the run from the drain to the curb is short enough to keep a steady fall, and when the water is clean rainwater from roofs, lawns and hardscape. It does not make sense when the yard sits below the street, because water will not run uphill without a pump.

How a cored curb outlet is built

A curb outlet is a small job with a few parts that all have to be right. If one of them is wrong, water backs up, the pipe silts in, or the curb cracks around the hole.

Coring through the concrete curb

We cut the opening with a core drill and a diamond bit, sized to the pipe, usually 3 or 4 inches. Coring gives a clean round hole without hammering, so the curb face stays sound. The hole sits low in the curb face so the pipe discharges just above the gutter flow line.

The pipe run under the parkway and sidewalk

From the yard, solid PVC or SDR pipe runs to the curb with a fall of at least 1/8 inch per foot, and 1/4 inch per foot where the grade allows. Where a sidewalk sits between the yard and the curb, the line either passes underneath it in a bored or trenched crossing, or the sidewalk section is cut and replaced. Some cities ask for a steel sidewalk drain plate instead, a shallow covered channel set flush with the walk.

The outlet fitting

The pipe ends in a curb outlet fitting, a cast or molded adapter that sits flush with the curb face and is grouted or set in concrete. Many include a flap or grate that keeps rodents and gutter debris out of the pipe while letting water push through.

Permits and rules for draining to the street

The curb, gutter and usually the sidewalk strip belong to the city, not the homeowner. Cutting into them is work in the public right-of-way, and most cities require an encroachment permit or a written approval before anyone cores a curb. Rules on hole size, fitting type and sidewalk crossings vary from city to city, so we check with the City of Roseville, or the city or county for the property, before the job starts.

The other rule is about what goes into the pipe. Street gutters lead to storm drains, and in this area storm drains feed local creeks such as Dry Creek, Linda Creek and Cirby Creek. Rainwater from roofs and yards is what a curb outlet is for. Pool water, wash water, paint, oil or anything from a sewer line should never go to the gutter, and local rules on draining a pool vary, so ask before you do it.

Signs a curb outlet is the right fix for your yard

A curb outlet usually fits when you see some of these:

• Downspouts empty into flower beds near the foundation, and the soil stays wet for days after rain.
• A yard drain or catch basin exists but its pipe ends in the lawn, where water bubbles back up.
• Water runs along the side yard toward the street but stops at a low spot short of the sidewalk.
• The front yard is clearly higher than the gutter, with a short, straight route between them.
• An existing curb outlet is cracked, buried or blocked and water no longer reaches the street.

Curb outlet or dry well: choosing where the water goes

When the grade to the street is too flat, or the drains are in a back yard far below the curb, a curb outlet may not work. In that case we look at a dry well, which holds water underground and lets it soak into the soil. A dry well needs soil that drains, and heavy clay or a high water table can make it fill and stay full.

A curb outlet has no soak-in limit. It moves water as fast as the pipe carries it, which is why we prefer it when the elevation works. Some yards use both: front drains run to the curb, and a dry well handles a back corner that cannot reach the street.

How a curb drain outlet installation goes, step by step

On a typical job the work follows the same order.

Measuring the fall

We shoot elevations from each drain inlet to the gutter flow line with a laser level. If the numbers do not give a steady fall over the run, we say so and talk about other options before any digging.

Locating utilities and getting approval

Underground lines are marked before digging, since water, gas, power and irrigation lines often cross the parkway strip. The permit or city approval is in hand before the curb is cut.

Trenching, laying pipe and coring

We trench from the yard to the curb, bed the pipe on sand or gravel, and check the slope along its length. The curb is cored last, the fitting is set, and the line is connected to your downspouts, catch basins or French drain.

Testing and restoring

We run water through the system with a hose and watch it leave at the curb. Then the trench is backfilled and compacted, and turf, rock or concrete is put back.

Roseville conditions that affect curb outlets

Roseville gets nearly all of its rain in the wet season, generally October through April, and very little from June to October. That means a curb outlet can sit dry for months, then take a winter storm all at once. A pipe that has slowly filled with dust, leaves or roots over the summer finds out in the first big rain.

Much of the city is newer single-family development, and many of those lots were graded to shed water toward the street. That often makes curb outlets practical. Older homes near the historic downtown can have drains that were never piped to the curb, or outlets that have been paved over during later sidewalk work.

Keeping a curb drain outlet flowing

Upkeep is light. Before the wet season, clear leaves and grit from the gutter in front of the outlet, since a dam of debris there pushes water back into the pipe. Check that the flap or grate opens freely. Clean the strainers on yard catch basins and downspout connections, because most clogs start upstream.

If water still backs up, a camera inspection shows whether the pipe has a sag, a root intrusion or a crushed section under the sidewalk. Those are fixable by replacing the bad length rather than the whole line.