Land Use, Septic & Wells

Program Overview

All homes must have a safe water supply and a system for proper disposal of sewage and wastewater. Some people in San Mateo County live in areas that do not have a community water supply or a municipal sewer system. If you live in one of these areas, you must install your own water and sewer systems.

The goal of the Land Use Program is to help people who live in these areas with these water supplies or sewage disposal systems. Inspection staff also certify septic system installers and percolation testers.

Permit Applications 

All people who install individual water supplies or sewage disposal systems must have a permit from Environmental Health.

Application approval can take some time. Inspection staff check permit applications to make sure that all installations will be safe for neighboring properties and surrounding areas. Often, community members and/or the County Board of Supervisors must approve the installation of new systems, as well.

Septic Application
Septic Pumper Trucks & Business Application
Water Well Application
Land Use Review Application

Onsite Wastewater Treatment Systems (OWTS)

Onsite Wastewater Treatment Systems (aka Septic Systems)

If you live in an area of San Mateo County that does not have a municipal sewer system, you must dispose of sewage and wastewater on your own property. In San Mateo County, the only approved system is a septic system. In a septic system, wastewater goes into a large underground tank. Pumping removes the solids in the tank. The liquid in the tank flows into the ground through a system of underground pipe and gravel. Over time, as the liquid soaks into the ground, organisms that live in the ground and in the sewage eat the organic materials and the harmful bacteria die.

Inspection staff will observe and approve the work when you need to install, repair, alter or destroy an individual sewage disposal system.

They do this by:

• reviewing the proposed location for the system;
• observing soil testing;
• reviewing and approving plans;
• observing the construction of the system;
• verifying when a system has been destroyed safely; and
• certifying installers and percolation testers.

When a septic system fails, sewage may back up into a home or it may pool onto the ground. Inspection staff investigate complaints of failed septic systems to make sure there is no hazard to public health.

Resources

State Onsite Wastewater Treatment System (Septic) Policy
Perc Testing Device Instructions

OWTS Ordinance

The current Onsite Wastewater Treatment System (OWTS) Ordinance  was approved by the County Board of Supervisors and was effective on February 4, 2016. Our Onsite Systems Manual (OSM) (May 11, 2016) is the implementation manual for the new OWTS Ordinance. The Ordinance and OSM are designed to comply with recent State OWTS Policy.

San Mateo County’s Local Agency Management Program (LAMP) pertains to the oversight of onsite wastewater treatment systems (OWTS) within the County of San Mateo, California. The LAMP was prepared in accordance with the requirements of the State Water Resources Control Board’s (SWRCB) Water Quality Control Policy for Siting, Design, Operation, and Maintenance of Onsite Wastewater Treatment Systems, dated June 19, 2012, also referred to as the “OWTS Policy”, and submitted to the Regional Water Quality Control Board, San Francisco Region, on May 11, 2016.  The LAMP was been prepared by San Mateo County to obtain approval for OWTS management under Tier 2 of the OWTS Policy. As such, it is intended to allow the County to continue providing local oversight of OWTS by implementing practices that: (a) are suited to the conditions in San Mateo County; (b) meet or exceed the environmental protections of the “default” siting and design requirements for OWTS identified in Tier 1 of the SWRCB OWTS Policy; and (c) ensure the best opportunity for coordinated and comprehensive management of OWTS, public health and water quality in San Mateo County.

Onsite Systems Manual

Complete Onsite Systems Manual

By Section:

Section 0: Introduction with Glossary of Terms
Section 1: Policies and Administrative Procedures

Clarification of Connection to Sanitary Sewer

Section 2: Site Investigation Requirements and Procedures
Section 3: Design and Construction Requirements for Conventional OWTS
Section 4: Alternative OWTS Requirements
Section 5: OWTS Performance, Monitoring and Evaluation
Section 6: Advanced Protection Management Program

Septic Pumper Businesses & Trucks

In San Mateo County, all persons who engage in pumping or cleaning or engage in the business of pumping or cleaning of onsite wastewater treatment systems (OWTS; septic systems), holding tanks, or portable toilets, or removing other accumulations of septage, or dispose of the cleanings thereof, must have a current certification from Environmental Health Services as described in the Onsite Systems Manual.

In addition to permitting the septic pumper businesses, each pumper vehicle operating within San Mateo County must be inspected by Environmental Health Services annually based on criteria in the Onsite Systems Manual, and must bear a current Environmental Health Services Vehicle Identification Permit, unique to each vehicle. 

Resources

Septic Pumper Trucks & Business Application
Septic Pumper Truck Spill Guidelines
Septic Tank and Chemical Toilet Cleaners Report

Planning & Building Application Review

For parcels served by an onsite wastewater treatment system (OWTS; septic system) and/or parcels served by an individual domestic water supply well, Environmental Health Services is required to evaluate that there is adequate and appropriate sewage disposal and/or potable water supply for the proposed planning and building project. Therefore, San Mateo County (unincorporated), as well as Town of Woodside, Town of Portola Valley, and City of Half Moon Bay planning and building departments, refer projects for review by Environmental Health Services that may require a new OWTS, affect an existing OWTS, and/or include water supply other than a regulated water system that may be impacted by the proposed development/improvements (i.e. bedroom additions, construction outside of building footprint, accessory structures, decks, grading, drainage, landscape, hardscape, etc.).

For projects referred through County Planning and Building, Environmental Health Services review fees are paid through the Planning and Building Department. For projects referred through town or city planning and building departments, a separate Land Use Review Application with applicable fee must be submitted to Environmental Health Services. Note: application and fees must be received and processed prior to staff review of the project. 

Land Use Review Application

Wells

Resources

Water Well Application
Water Well Construction Procedures
Heat Exchange Bores/Wells
Water Well Ordinance
Quality Standards - California Title 22 Primary Inorganics

Individual Water Supplies

Inspection staff regulate all domestic and agricultural water wells and springs. Before you move into your new residence or business, they will make sure that your water supply is safe. They do this by:

• checking that all wells and springs are constructed properly; 
• certifying that water output meets local requirements; and
• monitoring and reviewing chemical and bacterial tests

Disinfection of Wells 

• Introduce one cup of household bleach into the well through opening at the slab top or casing. Newer wells should have a capped gravel pack pipe or disinfection pipe at the slab which can be opened. For wells deeper than 50 feet, introduce two cups of household bleach into the well.
• Add five gallons of water chlorinated with ½ cup of household bleach to the well to force the solution out into the surrounding formation.
• Operate the well pump until a distinct odor of chlorine can be detected in the water after the pressure tank or somewhere at the house.
• If the well was operational during the storm, and there is a risk that house lines are contaminated, run the water until the smell of chlorine can be detected at the kitchen and bathroom sinks.
• Allow the chlorine solution to remain in the well and water lines for at least four hours, preferably overnight.
• After disinfection, pump the well and run the water in the house until the odor of chlorine is no longer detected.
• To collect a sample to be tested for bacteria, it is best to use a container provided by the laboratory. If one is not available, use a 12 oz. or greater glass jar which has been sterilized by boiling (lid included). If possible, take the sample directly from the well or an outside tap. Run the water for one minute, take sample being careful not to touch the inside of the lid or jar. Transport to a commercial laboratory or the County Public Health Lab. The sample should be on ice and arrive at the lab no more than 5 hours after sample collection for valid results. Test for “Coliform Bacteria, presence/absence.” Call the laboratory first to ensure they can do the required analysis. The County Public Health Lab is located 225 W. 37th Avenue, Room No. 113, San Mateo, CA 94403 | (650) 573-2500

Well Use in Droughts

Our goal, especially during droughts, is to work with you to maintain an adequate and safe water supply for your household. If your well or spring is not producing enough water for your needs, please review the information in these frequently asked questions as we continue to seek resources and options for homeowners using wells for water supply in rural San Mateo County.

1. My well is not producing enough water for my home, what should I do?

• You should start working now to secure a sustainable water source for your home … deepen your well, drill a new, deeper well, or connect to a public water system if possible. 
• If you have a holding tank, you can contract for potable water delivery (see below for water haulers and requirements/suggestions). Hauling water to your home is a short-term solution to a long-term problem Make sure you are only using your water for the bare necessities—drinking, bathing, etc., and not for landscape irrigation.
• Make sure you have low-flow fixtures installed, and there are no leaks, drips or running toilets in your home that may be wasting water.
• Additional tips may be found here. 

2. Where can I find a licensed potable water hauler?

Potable water haulers are licensed by the California Department of Public Health. A current list of licensed potable water haulers sorted by county is available here (look for the current list under the “Licensed Water Haulers” section). There are currently only two licensed haulers listed for San Mateo County, so check surrounding counties too.

3. Do I have to use a licensed potable water hauler?

While unlicensed companies may deliver water to you, we strongly urge you to use a licensed potable water hauler because only licensed haulers have to meet rigorous quality standards.  Without knowing the quality of the water delivered, you may put you and your family at risk for contracting water-borne disease/illness.

4. Are there any precautions to take if I use hauled water?

There are inherent risks of contaminating hauled water during transfer and storage. It is recommended that, to the extent possible, water in your storage tank maintains a detectable chlorine level of 1 part per million.  Even with this precaution, it is not advisable to use hauled water for drinking or food preparation, including washing produce. If you have to use hauled water, please contact Environmental Health Services staff for more information on precautions to take, including disinfection protocols.

5. I don’t have a water holding tank … where can I find one?

​Your local plumber is a great resource for obtaining and installing a water holding tank. Nearby suppliers include, but are not limited to:

• Scotts Valley Sprinkler Co
  5010 Scotts Valley Dr.
  |Scotts Valley, CA 95066
  (831) 438-6450
  Brands of water storage tanks: Poly Processing, Norwesco, Bushman
   
• Make A Buck Co.
  3391 Cabrillo Ave|
  Santa Clara, CA 95051
  (408) 246-7932
  (800) 400-7932
  Type of water storage tanks: Plastic tanks

​You can also check your local yellow pages.

6. Do I need to get a permit to install a holding tank at my home?

It depends on the area of the county and size and configuration of your desired holding tank. Contact the San Mateo County Planning and Building Department at (650) 599-7310 or (650) 599-7311. No separate Environmental Health permit is required. Once the tank has been installed, Environmental Health is available to assist with any disinfection protocols.

7. If I need to drill a new well for my home, what permits will I need before beginning?

Prior to obtaining a drilling permit from Environmental Health Services, you may first need to work with the Planning and Building Department to determine if you need a Coastal Development Permit (CDP) or Coastal Development Exemption (CDX). Once you have received approval from the Planning and Building Department or determine that no CDP or CDX is needed, you’ll need a drilling permit from Environmental Health Services. You can download the Water Well Application . Please note that if a CDP or CDX is needed, Environmental Health may work with the Planning and Building Department to request an emergency CDP or CDX to expedite the well permitting process. 

8. What resources are available to homeowners?

Environmental Health Services staff are available to assist you. Please contact them at (650) 372-6200 or GJSmith@smcgov.org. While there currently is no state or local drought relief funding available for individual well owners, we are lobbying the state to make funds available for affected water users. This is one more reason to let us know of any problems you may have—to inform our lobbying efforts. You can find additional state resources here.

9. How do I disinfect a well after a storm?

• Introduce one cup of household bleach into the well through opening at the slab top or casing. Newer wells should have a capped gravel pack pipe or disinfection pipe at the slab which can be opened. For wells deeper than 50 feet, introduce two cups of household bleach into the well.
• Add five gallons of water chlorinated with ½ cup of household bleach to the well to force the solution out into the surrounding formation.
• Operate the well pump until a distinct odor of chlorine can be detected in the water after the pressure tank or somewhere at the house.
• If the well was operational during the storm, and there is a risk that house lines are contaminated, run the water until the smell of chlorine can be detected at the kitchen and bathroom sinks.
• Allow the chlorine solution to remain in the well and water lines for at least four hours, preferably overnight.
• After disinfection, pump the well and run the water in the house until the odor of chlorine is no longer detected.
• To collect a sample to be tested for bacteria, it is best to use a container provided by the laboratory. If one is not available, use a 12 oz. or greater glass jar which has been sterilized by boiling (lid included). If possible, take the sample directly from the well or an outside tap. Run the water for one minute, take sample being careful not to touch the inside of the lid or jar. Transport to a commercial laboratory or the County Public Health Lab. The sample should be on ice and arrive at the lab no more than 5 hours after sample collection for valid results. Test for “Coliform Bacteria, presence/absence.” Call the laboratory first to ensure they can do the required analysis. The County Public Health Lab is located 225 W. 37th Avenue, Room No. 113, San Mateo, CA 94403 | (650) 573-2500.