How often should a commercial building have its drains cleaned or jetted?

The reviewed IPC maintenance provision and Phoenix/Scottsdale program documents do not prescribe one fixed cleaning interval for all private building drain lines. Individual facilities may have additional permit or maintenance conditions; confirm the rules applicable to the property. The plumbing code puts the job on the owner instead. The ICC's International Plumbing Code, in Section 102.3, says plumbing systems "shall be maintained in proper operating condition in accordance with the original design in a safe and sanitary condition." It adds that "The owner or the owner's authorized agent shall be responsible for maintenance of plumbing systems." That's a duty to keep drains flowing, not a calendar.

The grease rules are stricter, but they cover the device, not the pipes. Scottsdale's inspection form quotes city code requiring that grease interceptors be "pumped out or cleaned out completely not less than once every ninety (90) calendar days." That's the interceptor. Our pages on how often to pump a grease trap and grease trap pumping vs cleaning vs jetting cover that side, and why pumping the trap doesn't clean the lines.

Line jetting does show up in city programs, just without a set interval:

• Phoenix ties it to grease habits. Phoenix's FOG manual says keeping grease out of the plumbing reduces the chance of a blockage, "reducing the need for the routine jetting of the sewer lines."
• Scottsdale can order it. Among the follow-up actions on Scottsdale's restaurant inspection form is "Hydro-Jet Building Waste Lines," listed next to pumping the device and sending in pumping invoices.
• Flagstaff warns about doing it wrong. Flagstaff's FOG manual says owners "will be held financially responsible for jetting activities occurring on their property that discharge FOG or cause SSOs or other downstream obstructions to the sanitary sewer." Jetting has to remove grease, not just push it into the city's pipe.

So the rules push you toward jetting when grease builds up, and hold you responsible if it causes a backup. The maintenance plan must fit the building and any applicable permit or local requirements.

Five things set it: how much grease goes down, whether roots can get in, the pipe's shape and material, how often the line has stopped up before, and what a camera shows after cleaning. The first two are the big ones in Phoenix. Phoenix's sewer cleaning FAQ says the biggest problem in its sewers "is coagulated grease and cooking oil," and that the second is roots, which "can find their way through the pipe joints or other openings and form a root ball once inside the pipe." Private lines inside and under a building fail the same ways.

Grease is the driver for restaurants. It goes down warm, cools in the pipe and sticks to the walls. That's why kitchen branch lines, floor sinks and the line from the kitchen to the interceptor usually need attention more often than anything else in a building. Our page on grease in the sewer lateral after the trap covers the pipe on the far side of the interceptor, which can build up too.

Roots come back after cutting. Jetting or cutting clears the pipe but leaves the opening where roots got in. That's why a root line tends to need a steady schedule until the pipe itself is fixed. See how to keep tree roots from coming back after hydro jetting.

Pipe condition changes everything. A belly in a sewer line holds water and grease, so it fills back in faster than a straight run. Older cast iron drain pipe can grow rough scale that catches debris. Neither shows up until someone runs a camera.

Use the same method sewer utilities use: look first, clean where it's needed, and let the results set the timing. Phoenix's sewer FAQ says that "Before sewer lines are cleaned, a sewer TV crew goes out and inspects sewer lines with a remote camera to look for obstructions and evaluates the integrity of the line." EPA's fact sheet on sewer cleaning reports that Garland, Texas, found inspections to be the more valuable half of the work, recommending "70 inspections and maintenance activities for every 30 cleanings." EPA's fact sheet adds that "Inspections are considered more important because they help define and prevent future problems."

Here's how that plays out for a building:

1. 1Start with a baseline. Have the main lines cleaned, then run a camera through them. The video shows pipe condition, bellies, root entry points and anything that should be repaired. Our page on what a commercial sewer camera inspection finds explains the report.
2. 2Look again later. Run the camera again after a set time. Pick a shorter gap for a busy kitchen line and a longer one for restroom lines.
3. 3Adjust. If buildup is heavy at the second look, clean more often. If the line is still clean, stretch the interval.
4. 4Clean each line on its own clock. The kitchen line, the restroom stack and the building sewer rarely need the same schedule.
5. 5Keep a log. Write down the date, the lines cleaned, the method and what the camera showed. It's the record that sets next year's schedule, and it's handy if a city inspector asks what you've done.

EPA's fact sheet says a utility maintenance plan should weigh "Problems- frequency and location," and a building works the same way. The line that stopped up three times last year gets the shortest interval.

### Jetting or snaking?

For routine grease and scale, jetting is usually the better tool. EPA's fact sheet describes jetting as a method that "Removes debris and grease build-up, clears blockages, and cuts roots within small diameter pipes," and calls it "Efficient for routine cleaning of small diameter, low flow sewers." A cable machine punches a hole through a clog but leaves most of the grease on the pipe walls, so it tends to come back sooner. Our guide to hydro jetting covers when jetting fits and when it doesn't.

Don't lean on additives to stretch the schedule. Some Arizona cities restrict them; Flagstaff's FOG manual bans additives used "for the purpose of emulsifying FOG or passing FOG through a grease interceptor." See are enzyme grease treatments allowed in Phoenix before you buy them.

The building type sets where you start, and the camera sets where you end up. None of the sources we reviewed gives a set number of months by building type, so treat these as starting points to test, not rules:

• Restaurants and commercial kitchens. Grease makes the kitchen line the most frequent item in the building. Plan to camera and clean it on a short cycle, tie it to your grease interceptor service calendar, and tighten it if floor sinks start backing up.
• Multi-tenant retail and strip centers. One restaurant can load a shared line. Set the schedule by the worst tenant on the line, not the average.
• Apartments and hotels. Kitchen sinks in many units add up in the main lines. Look at the main building sewer on a regular schedule.
• Offices, warehouses and light retail. Restroom lines with few sinks can go a long time between cleanings. A camera look every so often, plus a cleaning when it shows buildup, is often enough.
• Any building with trees near the lateral. Roots set their own clock until the pipe is repaired.

Watch for signs that the schedule is too long: slow floor sinks, gurgling, sewer odor in the kitchen, or the same line stopping up again. If your commercial kitchen drain is overflowing or your grease trap is backing up into floor sinks, the line is past due. For a building-wide plan that includes drains, backflow and water heaters, see our commercial plumbing preventive maintenance plan. Homeowners should use our residential drain cleaning guide instead.

HQ Plumbing & Air handles commercial drain cleaning, including hydro jetting and camera inspection of building drain and sewer lines, with upfront pricing and free estimates. We're licensed and insured and available 24/7 when a line backs up.