The Utilities Department delivers safe, high-quality drinking water to San Luis Obispo residents around the clock. To help keep the water system protected for the entire community, certain properties must install and maintain approved backflow prevention devices.

Protecting Your Drinking Water

Backflow happens when water flows the wrong way and flows back into the drinking water system. This can pull or push on-site contaminants, like dirt, chemicals, or fertilizers into the clean water supply. Backflow prevention devices stop that from happening and help keep our community’s drinking water safe from on-site hazards. 

What is a Cross-Connection?

A cross-connection happens when drinking water pipes are linked to something that could pollute or contaminate the water supply. If pressure changes during an event such as a main break or fire hydrant use, water can flow the wrong way (called backflow) and pull unsafe water into the pipes we all share.

Cross-connections can allow pesticides, fertilizers, cleaning chemicals, or even bacteria to enter our drinking water. That means one person’s unsafe connection could put the entire neighborhood at risk. 

How does it work?

1. Hose submerged into a bucket of cleaning chemicals creates a cross-connection.

2. Main break causes a drop in system water pressure. 

3. Chemicals are back-siphoned into the City's water system, causing potential harm to other users. 

Common Hazards

How Can You Protect Your Home or Business?