What is a well yield test?

A well yield test measures how much water your well can produce over a sustained period, expressed in gallons per minute (GPM). The test involves pumping water from your well at a controlled rate while monitoring the water level to determine the maximum sustainable production capacity.

How much does a well yield test cost in San Diego?

A basic well yield test in San Diego typically costs $200-$400, while a comprehensive 4-hour sustained yield test required for real estate transactions costs $400-$800. Extended 24-hour tests for agricultural or commercial wells can cost $800-$1,500.

What is a good GPM for a residential well in San Diego?

For San Diego residential wells, 5-10 GPM is considered good, providing adequate water for a typical household. Wells producing 3-5 GPM are marginal but workable with storage tanks. Less than 3 GPM may require supplemental storage or water conservation measures.

When should I get a well yield test?

You should get a well yield test when buying or selling property with a well, if you notice decreased water pressure or flow, before adding water-intensive features like irrigation or pools, if your well hasn't been tested in 5+ years, or after drought conditions to assess well recovery.

How long does a well yield test take?

A standard residential well yield test takes 2-4 hours of continuous pumping. Real estate transactions in San Diego County typically require a minimum 4-hour sustained yield test. Agricultural or high-capacity wells may require 8-24 hour extended tests.

Can a well's yield change over time?

Yes, well yield can change significantly over time due to aquifer depletion, drought conditions, increased neighborhood pumping, mineral buildup in the well screen, or pump deterioration. Regular testing every 3-5 years helps track changes and plan accordingly.

What happens if my well fails the yield test?

If your well produces insufficient water, options include well rehabilitation to restore flow, installing a storage tank system, deepening the existing well, hydrofracking to open rock fractures, or drilling a new well in a better location. A qualified well contractor can recommend the best solution.

Is a well yield test required for San Diego home sales?

While not legally required in all cases, most lenders require a well yield test for mortgage approval on properties with private wells. San Diego County recommends a minimum 4-hour sustained yield test demonstrating adequate production for the intended use.