Why Your Pool Loses Water in Winter
When Julie in Sheridan walked outside one chilly morning, she noticed the pool water sitting lower than usual. At first she thought she imagined it, but the next week it dropped even more. Since nobody had been swimming and it wasn’t hot outside, she wasn’t sure how the water disappeared. It wasn’t evaporation season, and nothing looked obviously wrong.
Winter water loss is a real thing in Northern California—and it confuses a lot of homeowners. When it’s cold, quiet, and nobody is using the pool, dropping water levels often go unnoticed until the problem becomes big enough to see.
Why Pools Lose Water in Winter
Even though it’s cooler outside, your pool still loses water during winter. The causes are different from summer, but they still add up.
Cold weather, rain, and wind can lead to:
Evaporation on windy days
Leaks that show up only in cooler temperatures
Water displacement from winter debris
Minor cracks that open as temperatures shift
Because you aren’t checking the pool as often, these small issues become easier to miss.
Winter Evaporation Is Sneaky
Most people assume evaporation only happens during summer heat. But in winter, evaporation can increase on dry, windy days when the air pulls moisture from the surface faster than expected.
You may not notice the change immediately, but week by week, the water level slides down just enough to matter.
Temperature Changes Can Cause Small Leaks
Concrete expands and contracts with temperature shifts. During colder months, tiny cracks sometimes open up just enough to let water escape slowly.
These leaks are small but steady. Over several weeks, they create noticeable water loss.
How to Tell If It’s a Leak or Evaporation
The easiest test is the bucket test.
Fill a bucket with pool water, set it on the top step, and mark the water level inside and outside.
If both drop at the same rate, it’s evaporation.
If the pool drops more than the bucket, there may be a leak.
Winter is the best time to run this test because everything else is stable.
Watch the Equipment Area
Water loss often shows up around the pump pad before anywhere else. Look for:
Damp soil near plumbing
Small puddles around the pump
A steady drip from valves
Air bubbles coming from return jets
Cold weather makes plastic fittings contract, which can create temporary leaks.
How To Prevent Winter Water Loss
Some simple habits help keep your winter water levels steady.
Check the Water Level Weekly
Even when you’re not swimming, a quick glance helps you catch problems early.
Keep the Pump Running Daily
Circulation helps move water through the system and lets you spot leaks faster.
Remove Debris Often
Leaves and branches weigh down the water, splash it out, and create low spots around the pool edge.
Inspect Seals and Fittings
A small drip in winter becomes a big problem in spring.
When To Call a Professional
If your pool continues losing water after simple checks, it’s time for a full inspection. Leak detection, seal replacements, and plumbing tests help prevent bigger repairs later.
Keeping Your Pool Healthy All Winter
Julie eventually discovered a small leak at one of her return lines—something she never would’ve noticed without checking her water level. Once it was repaired, her pool stayed steady all winter long.
American Dream Pool & Spa Service helps homeowners in Lincoln, Rocklin, Roseville, Granite Bay, Sheridan, Loomis, and Penryn keep their pools healthy through every season. If your pool is losing water this winter, we’ll help find the cause and fix it fast.
