Catch Basin Cleaning and Storm Line Jetting in Phoenix

We clear the basin, then we jet the whole line behind it. Two steps, in that order. First the debris comes out of the basin so it does not get pushed down the pipe. Then we run the jetter through the storm line all the way to the retention area and flush it out. That second step is the one that gets a parking lot to drain.

Clearing a grate by itself looks like progress. The pond at the inlet drops for a minute. But whatever blocked the pipe is still in the pipe, and the next hard rain finds it. We hold an Arizona A-12 license, the class built around storm drain pipe, and this is the work it covers.

Because the blockage is usually past the basin. A catch basin is a box under a grate with a sump below the outlet pipe. Sediment settles in that sump, and the cleaner water leaves through the outlet and runs down a storm line toward the retention area or a drywell. Silt, roots and packed sand build up in that line over time, one monsoon after another.

The Stormwater Center reports that once a sump is more than 60 percent full, it stops catching sediment well and a fast storm can flush the old material downstream in a pulse. That pulse is exactly what plugs the line and the inlet to the retention basin. Our catch basin FAQ goes through how the sump works.

At least once a year for a look, and more often on a dusty or tree-heavy site. No Valley city writes one number that fits every lot. Chandler's manual has drywells inspected yearly and cleaned on a fill trigger. Phoenix's code makes the owner keep the controls working and keep five years of records. The Stormwater Center's 60 percent sump figure is the practical test.

Two timing points. Right before the monsoon, in late spring, is the cheapest time to catch a problem. Right after a storm that left water standing is the other: if the lot held water for more than 36 hours, treat that as the signal, because both Phoenix and Maricopa County use 36 hours as the line for retention.

Because the retention area is where the line is supposed to deliver. If you jet only the first twenty feet, you move the plug, not remove it. We follow the run to the basin or the drywell inlet and flush it out so the full path is open. In a lot with several catch basins feeding one line, we work the whole system, not each grate on its own.

For the sanitary side of a building, we jet and camera lines too. A storm line is a separate system with different rules. Our FAQ on storm and sanitary lines explains why they must never be connected.

That is a fair question to ask any contractor. Phoenix's code allows only stormwater into a retention basin or the storm drain system, with a short list of exceptions. Silt and wash water from cleaning are not on that list. A catch basin job should end with the material hauled away and the line flushed in a way that does not turn the retention basin into the dump site. Ask for that in writing before you sign.

If the basin and line are clear and the lot still holds water, the problem is farther down: the drywells in the basin, the soil, or a design that was undersized. Our drywell cleaning page covers the first. The second and third belong to a civil engineer, and we will say so rather than clean something that is not the cause. The step-by-step check is on the parking lot and retention basin drainage page.

If the water backing up is in a restroom or kitchen, that is a sanitary line. Start with commercial drain cleaning or hydro jetting.

Tell us the address, how many grates the lot has and where water stands. We give free estimates, and you get the price upfront before work starts. HQ is licensed and insured and takes emergency calls 24/7, including after a monsoon storm.