Los Osos Groundwater Basin

Retrofit Requirements:

The Retrofit-On-Sale Program (Title 8) requires retrofit verification for all homes before sale. The Retrofit to-Build Program (Title 19) requires all new development that uses water from the Los Osos Groundwater Basin to retrofit older plumbing fixtures in existing homes and businesses to save twice the amount of water the new development will use.  

The retrofit requirements apply to properties inside and outside of the Sewer Service Area/Prohibition Zone (see map below).


Los Osos Sewer Service Area/Prohibition Zone Map:

To find out if your property is within the Sewer Service Area/Prohibition Zone, use the map below.‚Äč



If you’re having trouble, please feel free to contact the Department of Planning and Building

Click here to view a PDF map of the Los Osos Prohibition Zone


Click here for more information about new development using water from the Los Osos Groundwater Basin