Storm drain cleaning cost in Northern California typically runs $250 to $750 for a single residential or small commercial drain, and $750 to $3,000 or more for a parking lot, ranch culvert, or county system with years of sediment built up. The number that matters more than the price is the sediment depth: once a catch basin sump is 40 to 60 percent full, it stops draining the way it's supposed to.
Walberg, Inc. has run desilting and cleanout work on ranch ponds and drainage systems across Tehama, Butte, and Shasta counties since 1999, and the storm drains we get called out to are rarely the ones that backed up once. They're the ones that have been quietly filling with silt, gravel, and leaf litter for two or three winters, and nobody noticed until a parking lot started ponding or a culvert under a ranch road washed out.
What drives the cost of storm drain cleaning
| Cost factor | What it means |
|---|---|
| Sediment volume | A basin cleaned every year or two is a couple hundred dollars. One that's been packed solid for several winters can mean pulling material with an excavator instead of a vac trailer. |
| Access | A curb inlet on a city street is easy to reach. A culvert at the back of a 40-acre parcel means moving equipment to get to it. |
| Number of structures | Pricing one catch basin is a different job than pricing a county's or an HOA's entire system under one contract. |
| Disposal | Sediment from a storm system can carry oil residue, road grit, or trash that changes how and where it gets hauled. |
| Equipment needed | Hand tools and a vac trailer cover most small jobs. Heavy buildup calls for an excavator and dump trucks, closer to the equipment we run for pond cleaning than a typical drain-clearing service. |
How often storm drains actually need cleaning
There's no single statewide schedule that applies to every drain. The EPA's guidance on storm drain system cleaning points to inspecting and cleaning catch basins on a schedule tied to how fast they fill, generally once or twice a year for most sites, with commercial and industrial properties often needing it more. The rule of thumb we use in the field: once sediment fills somewhere around 40 to 60 percent of the sump, it's time. Wait past that and the basin traps less debris during the next storm than it's designed to.
Cities and counties running a storm sewer system under a state stormwater discharge permit don't get to treat this as optional. The State Water Resources Control Board's municipal stormwater program requires permittees to inspect and maintain catch basins and control structures before the rainy season starts, not after, and to document that it happened.
Signs a catch basin or storm drain needs cleaning
Water pooling around the grate after an ordinary rain is usually the first thing anybody notices. Past that, we look for standing water that takes hours to drain instead of minutes, a sour or stagnant smell coming up from the grate, and a gurgling sound when water finally starts moving. On older systems, a sunken or cracked grate is often a sign that sediment has undermined the structure underneath it, not just filled it up.
The reliable way to check is to drop a rod down to the bottom of the basin and measure from the sediment line to the outlet pipe. If sediment covers a third or more of that distance, the basin needs to be pumped or dug out before the next storm, not after it.
Who's actually responsible for cleaning it
This trips up a lot of property owners. In general, a storm drain in the public right-of-way or inside a dedicated drainage easement is the city's or county's job to maintain. A storm drain or catch basin on private property, serving a private parking lot, a subdivision where the drainage was never dedicated to the county, or a commercial site, is the property owner's or HOA's responsibility, not the county's. If you're not sure which category your drain falls into, your county's public works or environmental health department can usually tell you from the parcel record.
Why late summer is the window to get this done
Grading contractors race to finish dirt work before the mid-October cutoff most Northern California counties enforce, and storm drain cleaning runs on a similar clock for a different reason. Once the rain starts, a system full of silt turns a normal storm into standing water, backed-up culverts, and washed-out gravel roads. Cleaning it out in August or September means the system is ready to do its job in November instead of getting worked on mid-downpour, when access is worse and everything takes longer. A shopping center parking lot in Chico that's never had its basins touched since it was built is exactly the kind of site where the first big November storm turns a maintenance job into standing water across half the lot.
Storm drain cleaning versus storm drain installation
These are two different jobs, and it's worth telling them apart before you call anyone. Storm drain installation means putting in new pipe, catch basins, or a drainage system where one doesn't exist yet, usually tied to a grading or building permit. Cleaning is maintenance on a system that's already there and was built correctly. If your drain works fine on paper and is just full of silt, you don't need a new system. You need it dug out or pumped.
We see this mix-up most on ranch properties, where a culvert that's simply choked with sediment from years of runoff off a hillside near Corning gets mistaken for a failed or undersized system, when it just needs to be dug out.
The bottom line
A single clogged residential drain is a job for a plumber with a jetter, not a general engineering contractor with an excavator. Where we earn our keep is parking lots, ranch culverts, and county or HOA systems that have gone years without a cleanout and need heavy equipment plus someone licensed to legally haul off what comes out. If you manage a system like that and aren't sure how bad the buildup is, contact us or request a free estimate before the rain turns a cleanout into a washed-out road.
Common Questions
How often should storm drains be cleaned?
Most residential and light commercial systems need a check and cleanout once a year, ideally in late summer before the rainy season starts. Sites with heavy debris, tree cover, or vehicle traffic, like parking lots or ranch culverts near unpaved roads, often need it twice a year. Municipal systems operating under a stormwater discharge permit are required to inspect their catch basins at least annually.
Who is responsible for cleaning storm drains in California?
Cities and counties maintain storm drains within the public right-of-way and inside dedicated drainage easements. Everything else, including private parking lots, HOA-owned drainage, and ranch culverts on private land, is the property owner's responsibility. Check with your county's public works department if you're not sure which category applies to your drain.
How do I know if my catch basin needs cleaning?
Look for water that pools and drains slowly, a sour smell near the grate, or a gurgling sound during rain. The reliable way to confirm it is measuring the sediment depth with a rod from the bottom of the basin to the outlet pipe; if sediment covers a third or more of that distance, it needs attention.
Does storm drain cleaning require a permit in California?
Cleaning out an existing storm drain or catch basin generally doesn't require a grading or building permit, since you're maintaining the system rather than changing it. If sediment removal uncovers a collapsed pipe or a section that needs replacing, that work falls under storm drain installation rules and may need one.
What happens if storm drains aren't cleaned before the rainy season?
A clogged system backs up during the first heavy storm instead of moving water where it's supposed to go. On a property, that usually means standing water and saturated ground near foundations. On a ranch, it often means a culvert failure and a road that needs regrading afterward, which costs more than the cleanout would have.