Mosquitoes only need a small amount of stagnant water to complete their life cycles. If left unmaintained, a single swimming pool can produce up to 3 million adult mosquitoes in one month. This is a huge public health challenge for all residents and the District.

Only two conditions will guarantee that mosquitoes do not grow: "Clean and Functional" or "Empty and Dry."  For pools that will remain full and non-operational during the Eaton Area Recovery Phase, the district may provide temporary treatments or mosquito fish distribution.

If a sign has been placed at your property, this indicates the District is currently monitoring your property for mosquito activity and has performed a treatment in the pool or large source of water. 

Types of Treatments

Mosquito fish

Mosquito fish, Gambusia affinis, is a topminnow from North America that is used around the world to control mosquito larvae. These fish are a low-maintenance, long-term treatment strategy to prevent the development of mosquitoes in non-functional pools. After initial assessment of the pool, the District will deliver the fish, free of charge.  

Please do not disturb the mosquito control treatment.

If changes or modifications to the source of standing water are needed, please contact the San Gabriel Valley Mosquito & Vector Control District promptly. This entails any of the following conditions:

Before: Removing fish or mosquito control treatment or draining the water. 

After: Restoring to a functional state or demolishing the poo. 

Acceptable Pool Conditions

Clean and Functional Pool

A "Clean and Functional" pool has a working pump and filtration system, and a regular chemical treatment schedule. Water must be clear, with little to no algae or debris. Once a clean and functional pool is confirmed, no further action is needed.

 Empty and Dry Pool

An "Empty and Dry" pool is completely dry and free of debris. Mosquitoes will continue to lay eggs and grow throughout mild winters so the pool will need to be emptied between rains. Standing water should not be left for more than four days.

Empty and dry pools need regular maintenance to stay mosquito-free. Long-term strategies, such as mosquito fish, may be available for non-functional pools.

Note: Swimming pools without water are prone to costly structural damage. The District in no way recommends that anyone empty their pool and encourages residents to research the negative impact of removing the water.