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      Department of Public Works Bureau of Sanitation

The Department of Public Works is responsible for making sure that water bodies affected by activities in the City of Los Angeles are pollution free. Bacteria tests of Santa Monica Bay water are taken daily near the Santa Monica Canyon flood control channel outlet. Results have too often exceeded safe levels of water contact recreation–especially during rainy weather. Water that carries harmful bacteria from failing septic systems can come into contact and pollute groundwater, rivers, and the ocean. Additionally, these bacteria can cause illness in swimmers.

Some homeowners in the Santa Monica Canyon have their own private sewage system either because hook-ups to the city sewer lines were not available when their homes were first built, or are still not available.

Other BMPs

Automotive Industry & Repair

Heavy Equipment Operators

Horse Owners & Equine Industry

Home Repair & Remodeling

Land or Air Transportation Facility

Landscape, Gardening & Pest Control

Manufacturing Facilities


Restaurant Industry

Sewage Systems

Water-based Cleaners

The consequences of a malfunctioning system are extremely costly and unpleasant not only for the family that owns one, but for the entire community, including the ocean environment. Thus, owners are required by law to keep their system functioning properly (L.A.M.C. Sec.

One potential source of bacteria in the watershed is malfunctioning sewage disposal systems. Septic tank failure have been documented on private properties in the Santa Monica Canyon area. This publication is a reminder about how to maintain a private sewage disposal system.

What is a Septic Tank?

A septic tank is the first stage of a private sewage disposal system. The septic tank is a watertight tank below ground and is usually made of concrete and sometimes of fiberglass or steel. It usually has one or two access ports a few inches below ground.

The tank receives household wastewater through an inlet pipe near the top of one side, settles out larger material to the bottom, breaks down waste material with in situ bacteria, and delivers the partially treated wastewater out another pipe on the other side to the disposal field via a distribution box.

What is a Disposal Field?

A disposal field is the second stage of the private sewage disposal system and completes the final breakdown of the wastewater with organisms in the soil. The disposal field consists of narrow trenches filled with gravel and perforated pipes that distribute the wastewater to the field.

With proper maintenance, a well designed system should last indefinitely; however, disposal field soils will normally clog if forced to handle the large particles that should settle out in the bottom of the septic tank. Routine pumping of the septic tank is imperative to avoid thousands of dollars in replacement costs of the disposal field.

What is a Seepage Pit/ "Cesspool?"

Some properties utilize a seepage pit instead of a disposal field when disposal fields are not suitable. Seepage pits are clay-lined excavations in the ground which receive septic tank discharges. Liquids seep through the pit’s bottom and sides.

Cesspools are septic tanks and seepage pits in the same excavation. Cesspools are usually installed as interim systems while waiting for the availability of a public sewer.

During rain events, runoff that flows down the 10,127-acre Santa Monica Canyon watershed can wash bacteria from septic systems and manure from horse corrals into Santa Monica Bay at Will Rogers State Beach.

Septic Tank Systems Maintenance

Reparing and Replacing

Some septic tanks need repairing or replacing. Always get expert advice and use qualified, licensed contractors. Older steel tanks have a 25-year service life and their lids may have lost load-bearing capacity due to corrosion. Concrete tanks may need replacing if cracks have developed that send sewage into the groundwater. Clogged disposal fields need to be dug out and replaced.


Sewage gases can be fatal; you should never attempt or need to attempt to enter a septic tank (even for minor repairs). A septage waste-hauler licensed by the City of Los Angeles can pump out your septic tank without needing to enter the tank. The waste-hauler will remove the septic tank contents (called septage) through an access port on top of the septic tank.

Pumping Frequency

Have your septic tank pumped out by a licensed septage waste-hauler on a regular basis. This will ensure that incoming solids have enough time to settle out.

Without adequate settling time, the solids would clog the disposal field and pollute downstream waters. Septic tanks may work without scheduled pumping; however, the system will eventually fail creating significant costs, odors, pollution and disruption of service. Replacing a disposal field could cost thousands of dollars.

Pumping frequency varies from one to three years based on household size, water use, tank capacity, and whether the disposal field is clogged. A garbage disposal will usually increase pumping frequency by about twenty percent. A licensed septage waste-hauler can determine your tank capacity and advise you on a recommended pumping frequency. If you are a new owner, you should determine when the tank needs to be pumped out. Some financial institutions require the tank to be pumped out and operational at the time of home sale. If you are unsure, you could call the previous owner or start your own pumping maintenance schedule.

General Maintenance

There is very little maintenance needed with a properly designed and operating septic tank. If your septic tank is shared with other properties, someone should be in charge of making sure the tank is pumped out. You should have damaged or missing baffles or tees replaced by a licensed contractor who understands confined spaces, the dangers of toxic sewage gases, and septic systems.


Additives usually contain yeast, bacteria, enzymes or chemical degreasers. Adding enzymes or bacteria usually do not harm the septic tank; however, they have not been scientifically proven to help either. Pumping is usually cheaper than the cost of additives.

System Failures

In overt system failure, the soil can no longer accept discharges and the wastewater may break out onto the ground surface where it can be conveyed into coastal and inland waters via the public storm drain system.

Putting too much wastewater into your septic tank can cause hydraulic overloading which may send bacteria and viruses into coastal waters via groundwater. If you suspect hydraulic overloading or wish to reduce the septic tank pumping frequency, consider eliminating the use of a garbage disposal and use composting or trash service for waste food material. Also, you may also want to consider…

Water Conservation

Make sure that leaking toilet valves, water fixtures, and pipes get fixed right away. Also, consider installing high-efficiency plumbing fixtures such as 1.6 gallons per flush toilets (older toilets use 3.5 to 5.0 gallons per flush), 1.5 to 2.0 gallons per minute fixtures and shower heads, and front loading washing machines up to 27 gallons per 10- to 12-pound load. These can result in a 30 to 70 percent reduction in total in-house water use.

Public Sewers

Most septic tanks were installed because public sewers were not available or were too far away at the time of development. Sewers have been built in some streets and easements in your area. Some are close by area properties and others are far away such as upper Mandeville Canyon Road. If you want more information about the location of the nearest sewer, the sewer connection process, and related fees please call the City of Los Angeles Department of Public Works at (213) 482-7050.

Here are a few simple steps you can take to maintain your septic system so as to maximize its efficiency, reduce problems and expenses, and provide protection for our beaches and bay.

Conserve water in your house to avoid system flooding—you will also cut costs.

Flush only human waste, wastewater, and toilet paper into septic tanks.

Inspect and pump out your system at least once every 3 years.

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Use only reputable, licensed septic waste haulers to pump out or repair your system.

Consider connecting to public sewers. Call the City of Los Angeles Department of Public Works at: (213) 485-3885 for more information.

Other resources include, the Department of Building and Safety, Private Sewage Disposal Systems (213) 847-3278.

Department of Water and Power, Water Conservation (213) 367-0944

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