On April 22, 2008, the Board of Supervisors approved two plumbing retrofit ordinances for the Los Osos and Nipomo Mesa areas. The ordinances address groundwater basin resource constraints by requiring both new and existing development to retrofit older, non-conserving toilets and shower heads with those that are water efficient.  The ordinances went effective May 22, 2008.

The Retrofit to-Build Program (Title 19) requires all new development that uses water from the Los Osos Groundwater Basin (LOGWB) to retrofit older plumbing fixtures in existing homes and businesses to save twice the amount of water the new development will use.  The amount of water savings calculated will be generated to water credits, whereas, the developer can use the retrofit credits to build a new single family home.  A total of 300 retrofit credits are required to build a new single family home.


Effective March 10, 2014, retrofit credits, with the exception of clothes washer retrofits, can no longer come from the Prohibition Zone (see map below). 

For more information on the plumbing retrofit programs, please click on the buttons below.

To find out if your property is within the Prohibition Zone, visit Permit View.


Instructions for Permit View:

  1. Enter the property address in the “Quick Search” box.

  2. Select the “Layers” tab which is two tabs below the “Quick Search” tab.

  3. Under the “Layers” tab, click the “Groundwater” tab.

  4. Check the box “Groundwater Basins at LOS III”. 

  5. Zoom in on Los Osos to see if your property is within the shaded area.

  6. If your property is within the shaded area, you are subject to plumbing retrofit policies, if and when you sell or build a new home.

  7. If you’re having trouble, feel free to give us a call.  Please refer to the “Contact” tab at the top of the page for the County’s Water Team contact information.