How to Prepare Your Pool for a Utah Winter

Utah winters don't mess around. Temperatures regularly drop into the teens and single digits along the Wasatch Front, and mountain areas like Park City and Heber can see well below zero. If your pool isn't properly winterized, that cold can crack pipes, damage pumps, and destroy heaters.

When to Close

The ideal window in Utah is late September to mid-October. You want to close before the first hard freeze but after the weather has cooled enough that algae growth slows down. Closing too early (while it's still warm) means the water under the cover can grow algae for weeks before it gets cold enough to stop.

If you're in the mountains, close by late September. Along the Wasatch Front, mid-October is usually fine. Keep an eye on the forecast — if a cold snap is coming, don't wait.

The Closing Process

Winterizing a pool isn't just throwing a cover on it. There's a specific sequence that protects your pool and equipment through months of freezing temperatures.

• Balance the water chemistry one final time. Adjust pH, alkalinity, and calcium hardness to their ideal ranges. Add a winterizing chemical kit — typically a combination of shock, algaecide, and stain preventer.
• Clean the pool thoroughly. Skim, vacuum, and brush everything. Any debris left in the pool will decompose under the cover and create stains.
• Lower the water level. Drop it 4-6 inches below the skimmer mouth. This prevents water from entering the skimmer and freezing, which can crack the skimmer body.
• Blow out the plumbing lines. This is the critical step. Using a shop vac or air compressor, force all water out of the pipes, pump, filter, heater, and return lines. Any water left in the lines can freeze, expand, and crack PVC pipes.
• Plug the return jets and skimmer. After blowing out the lines, plug everything to keep water from seeping back in.
• Drain the pump, filter, heater, and any other equipment. Remove drain plugs and store them somewhere you'll remember (we tape them to the equipment).
• Install the winter cover. A good safety cover keeps out debris, blocks sunlight (preventing algae), and provides a safety barrier.

The Most Expensive Mistake

Skipping the line blowing. Every year we get calls in spring from pool owners who thought lowering the water level was enough. It's not. Water trapped in underground pipes will freeze and crack the plumbing. Fixing underground pipe breaks means digging up your deck or yard — and that bill can easily run into the thousands.

What About Heated Pools?

Some pool owners keep their pools open year-round with a gas or heat pump heater. This is doable in Utah, but it requires commitment. The pool equipment needs to run continuously during freezing weather — if the pump loses power or the heater fails during a cold snap, you have hours (not days) before pipes can freeze.

If you go this route, make sure you have a freeze protection system that automatically kicks on the pump when temperatures drop. And have a backup plan for power outages — a generator or at least a plan to drain the lines quickly.

Spring Will Be Easier

A properly winterized pool opens up clean and clear in spring. Instead of dealing with a swamp, you pull the cover, reinstall drain plugs, fill the pool, start the equipment, balance the chemistry, and you're swimming within a day or two. The effort you put into closing pays off directly in how easy opening is.