How often should apartment sewer lines be jetted?

A jetter feeds water through a hose to a nozzle that sprays forward to break up a blockage and backward to drive itself along the pipe. On an apartment main, that scrubs the grease ring and sludge off the full width of the pipe and flushes it toward the street, where a cable only bores a path through the middle. Our page on what hydro jetting is has more.

Two buildings on the same property can need very different care. A building whose kitchens all drain into one stack picks up grease fast. A building with no trees near its lateral may run clean for years. Jetting every line on the same date spends the most effort on the lines that need it least, and can still leave a problem line backing up between visits.

City sewer crews work the same way. Phoenix's Water Services Department says a sewer TV crew inspects lines with a remote camera before they are cleaned, and the results decide whether a cleaning crew is sent. The city cleans about 25 to 30 percent of its more than 5,000 miles of sewer each year, so at that pace the average city line is cleaned about once every three to four years, with the camera deciding which lines go first. The EPA fact sheet describes the same idea: base cleaning frequency on how often and where problems occur.

• Grease from many kitchens. Phoenix names coagulated grease and cooking oil as the biggest problem in its sewers. In an apartment building, many kitchens share the same pipe, so grease builds up faster than in a house. Our page on why apartment kitchen stacks clog explains how.
• Roots. Phoenix names roots from trees and invasive shrubs, such as oleanders, as the second biggest problem. Roots enter through pipe joints and other openings and form a root ball inside the pipe.
• Pipe age and material. Older cast iron and clay lines can hold buildup in rough spots and open joints, so a camera run shows what each line is made of and what it holds.
• A history of backups. A line that has backed up before will usually back up again until its cause is fixed.

1. 1Start with a camera inspection of the building drains, the main and the lateral to the street, from the cleanouts. Our page on apartment community sewer camera inspection covers what it shows.
2. 2Jet the lines that need it, and leave the clean ones alone.
3. 3Camera again after jetting to confirm the line is clean and to note any cracks, offsets or sags. A broken line needs a repair, not more jetting.
4. 4Recheck the problem lines after a few months. If grease or roots came back, set that line on a shorter cycle. If it stayed clean, stretch the interval.
5. 5Keep a log of each line, its date, what was found and what was done, so the schedule improves each year.

Our guides on how often to schedule plumbing inspections at a multifamily property and what a sewer line maintenance contract should cover go further on the paperwork side.

Usually, for the lines that keep clogging. A cable opens a hole through a clog. A jetter cleans the grease off the whole pipe wall and flushes it out, so the line stays open longer. TEPPFA's jetting guidance favors lower pressure with higher water volume, which cleans the full pipe circumference and carries debris away with minimal risk of damage. For a single slow sink in one unit, a small cable is often all that is needed.

A cable machine run with the right size cable for the drain rarely harms a sound pipe. HQ never runs a large machine through a tub, kitchen or bathroom sink drain. It uses a 1/4 inch cable, 1/2 inch at most, run far enough to reach the main line. Damage comes from an oversized head or a pipe that was already failing, which is why the camera comes first.

In Phoenix, the sewer line from the building to the public main is the property owner's to clean, maintain and repair. The city's FAQ says it does not inspect sewer lines for homes and businesses and that everything from the connection back to the building is the owner's. Residents can help between visits. Phoenix asks people to let grease cool in the pan and scrape it into the trash, never down the drain.

HQ Plumbing & Air sends a two-person jetting team with a high-powered jetter. The team runs it from the cleanouts to pull grease and sludge out of the line and flush it to the city main, and cameras the line to confirm the result. See our apartment building drain cleaning and multifamily plumbing pages, or contact us to set up a camera inspection and a schedule for your property.