Water can start to collect in a backyard without weather-related precipitation preceding the event for a variety of reasons beyond a pool leak. Whatever the cause, it’s important to find the source of the water. Flooding can severely damage the lawn and any property made of materials that deteriorate when exposed to constant moisture. The water source might also be a cracked wastewater pipe or irrigation line. With a septic system leak, bacteria and toxins in the water can create a health and safety problem as well, especially for small children, immunocompromised adults and pets. This short guide can help you determine if the pool has one or more leaks. Check the following as soon as possible:

Water Loss

It might seem like common sense to check for water loss inside of the pool, but many homeowners forget to perform this basic inspection. Mark the pool interior with a height line and then check it daily. If you see more than a half-inch of water, then the pool likely has a leak somewhere. Water loss at less than these levels occurs from splashing and evaporation. If your pool automatically refills to take into account evaporation, check your water bill for high recent consumption or temporarily turn your automatic fill off.

Water Quality

Water appearance and odor can also help you narrow down the source of a backyard water problem. For example, if the water smells like feces, then you’re likely dealing with a septic tank leak. If the water seems clean and clear it may be an indicator of pool, irrigation or groundwater issue.

If you have the correct chemical levels in your pool there are two things you can use to chemically identify the water in the wet area as pool water.

First, if you have a salt pool you can test the water in the pool, in the wet area and the tap water for salt levels. Some salt is normal in all of these but it is usually pretty evident if the water in the hole matches the salt content of the pool.

Second you can check the levels of CYA or cyanuric acid (this is also known as stabilizer or conditioner). This is a chemical only found in pools. You can compare the level of cya in the hole and in the pool water.

Other chemicals will get filtered out and altered substantially by the soil chemistry but salt and cya are good chemical identifiers as long as you have the correct levels in the pool to start with and there has not been heavy groundwater dilution from rain or irrigation.

Irrigation issues can be identified by shutting the irrigation system off at the primary cutoff valve and monitor for the wet area to dry up.

When all else is eliminated the issue may be groundwater from a spring or up-slope drainage. The solution for this may be a French drain or sump pump.