Backflow Prevention


Since 1976, the backflow prevention program has been in effect pursuant to Section 408 of the Lake County Sewer Use Ordinance. The Ordinance was designed to provide protection from reverse sewer flow conditions in gravity-fed collection systems. Unfortunately, sewage doesn't always flow downhill as it should. Some residential developments are constructed in low-lying areas, areas with high water tables, or areas prone to source control problems (i.e. grease, roots, etc.). A properly installed and maintained backflow valve will prevent unexpected backup events and provide peace of mind through protection in the event of reverse flow conditions.

Sewage mishaps occur from a variety of causes including debris in the sewage collection system; accumulated cooking grease, and various other unusual obstructions. Sewer back-ups (surcharges) can also occur from temporary blockages for sewer repairs; volume overload from winter storms; illegal connections; localized flooding; inflow and infiltration; mechanical malfunctions at pumping stations; and power outages.

Often, sewer backflows result in property damage, high cleanup costs, loss of business revenue/customers, and legal disputes. The installation of a backwater valve can prevent many of these situations.


Section 408 of the Lake County Sewer Use Ordinance (Backflow Prevention Devices, Maintenance) states:

Where a sewer serves plumbing fixtures that are located less than one foot above the rim elevation of the upstream manhole or rod hole in the reach of the main sewer into which the side sewer connects, it shall be protected from backflow of sewage by installing a backflow prevention device of an approved type and in the manner prescribed by the Administrator. Any such backflow device shall be installed by the applicant for sewer service at the sole cost and expense of the applicant. The maintenance of the backflow device shall be the sole obligation of the permittee or his successor in interest. The District shall be under no obligation to ascertain that the backflow device continues in operating condition. (Order Number 871, 2-2-76).


There are a variety of backflow devices available and licensed plumbers are familiar with the installation of such devices. The backflow valve needs to be accessible for routine inspection and service, and the installation should allow the working components of the valve to be quickly and easily serviced. Backflow devices are typically located between the building cleanout and the building. A properly installed backflow valve will assure compliance with Section 408 of the Sewer Use Ordinance, reduce exposure, economic liability, and health hazards.

Backflow Suppliers

Special Districts cannot and does not endorse any one particular supplier or brand, but is always on the lookout for new and innovative technologies to help our customers.

Rules & Regulations

On May 9, 1985, the Lake County Board of Supervisors adopted Article VI to Chapter 9 of the Lake County Code (PDF) establishing a cross-connection control program for all district customers. In addition, Appendix D specifically includes a cross-connection program for Kelseyville County Waterworks District Number 3 customers.

View All