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Overview of Sanitary Sewer System

Pacifica's wastewater collection system is designed to convey water and waste from homes, businesses, schools and other public and private buildings to the Calera Creek Water Recycling Plant (CCWRP) where it is then treated.Every time a toilet is flushed or a shower is turned on, the water goes through a system of pipes and lift stations.

There are over 82 miles of wastewater mains in Pacifica and about half of them are 6” and 8” in diameter.Each building, public or private, has a 4" diameter lateral sewer that connects to the wastewater mains.The wastewater eventually arrives at one of the city’s six lift stations and is pumped to the CCWRP.  Please click on the link below to access "The 2021 Collection System Master Plan Phase 2 Update"-

The 2021 Collection System Master Plan Phase 2 Update

Sewer Backups

If you have a sewer backup, save time and money by calling Pacifica's Waste Water Treatment Plant at 650-738-4660 during working hours or police dispatch at 650-738-7314 during off hours before calling a plumber. Maintenance crews are available to respond to sewer service calls seven days a week, 24 hours a day, 365 days a year. They will determine whether the sewer problem is the city’s responsibility (at which time they'll fix it at no charge) or if the stoppage is the responsibility of the homeowner (at which time they'll then advise calling a plumber). Maintenance crews make every effort to respond to service calls within 45 minutes (average response time is within 30 minutes).

Sewer Backups Responsibility
Wastewater Mains - the city is responsible for backups in wastewater mains.
Side Sewers - property owners are responsible for maintaining side sewers. A side sewers is the sewer line beginning at the foundation wall of any building and terminating at the main sewer and includes the building sewer and lateral sewer together. Where the side sewer provides service to single-family residential units with common walls, condominiums, stock cooperatives, community apartments or other similar improvements, the obligation to maintain the side sewer shall be the homeowners' association or other entity responsible for the maintenance of the property and facilities owned in common. (Sec. 6-13.602 in the Pacifica Municipal Code).

Avoiding Sewer Problems



The two most common (and preventable) causes of sewer backups are:

  • Items put down the sink that should be put in the garbage instead
  • Invasive tree roots

Don't put grease, oil or egg shells down your sink. When grease and egg shells combine, they create a mixture similar to concrete. Oil sticks to the pipe at the waterline. Both of these conditions can clog the sewer line. Instead, keep a small container handy to contain these items. When the container is full, put it outside with the garbage.

Avoid trees with shallow, spreading root systems. Tree roots tend to grow toward sources of water, such as sewer pipes. Two of the most troublesome species of trees are the fruitless mulberry and the Modesto ash. If upgrading landscaping, save headaches and money by choosing trees with deep root systems. After selecting a tree, follow proper planting procedures and be sure to dig a hole deep enough to cut below heavy clay deposits (if a hole is too shallow, the tree's roots won't be able to penetrate the clay and they'll spread out horizontally - the tree won't be healthy and neither will your sewer system).

Hazardous Waste
Many consumer products are considered household hazardous waste. Never pour items like these into a sink or toilet:

  • motor oil
  • weedkiller
  • antifreeze solvents
  • gasoline
  • wood preservatives
  • paint
  • lighter fluid
  • insecticides
  • other common consumer products (read labels for disposal information)

For more information about household hazardous waste and a schedule of collection days and locations, call the San Mateo County Household Hazardous Waste Program at 650-363-4718.

Accessing Sewers for Maintenance
If you have a sewer maintenance hole (i.e., "manhole") on your property, sewer maintenance crews may need access to it for routine maintenance or emergency repair. Additionally, some homes have sewer clean-outs (smaller openings into which equipment may be lowered to inspect and evaluate the condition of the sewer service line) to which access may also be required.