Pool closing checklist for Ohio

Most of our customers close between mid-September and mid-October. The deadline is set by freezing weather. According to the National Weather Service's 1991 to 2020 normals, the average first fall freeze arrives around October 14 in Youngstown and Mansfield, October 19 at Akron-Canton and October 28 in Cleveland, where Lake Erie holds off the cold a little longer. The first frost comes a week or two earlier. Water that freezes inside a pump, filter or pipe can crack it, so the plumbing needs to be blown out and the equipment drained before hard freezes become routine.

The other signal is the water. Once it cools into the 60s, algae growth slows a lot, and chemicals added at closing last much longer. Close too early, in a warm stretch of September, and the water under the cover can grow algae through a mild October.

Then there are the leaves. Oaks and maples across Summit, Portage and Stark counties drop most of their leaves in late October, often after the first freeze. If you have a lot of trees, a mesh safety cover lets you close on time and deal with the leaves on top in spring. With a solid cover, some owners close the plumbing on schedule and net leaves off the cover through November.

• Test and balance the water: alkalinity, pH, calcium hardness and chlorine.
• Clean up anything already growing. Pentair's advice is to scrub the walls thoroughly before closing to reduce the chance of algae and scale over winter.
• Check the cover for holes or worn straps, and replace it now if it is failing.
• Gather supplies: winterizing plugs, skimmer gizmos, pool antifreeze if you use it, a closing chemical kit and water bags if you have a solid cover.

Balanced water matters more at closing than at any other time, because it will sit untouched for six months. Water that is out of balance can scale or etch surfaces over the winter.

1. Skim, brush and vacuum the pool. Get the leaves off the floor, because anything left in the water feeds algae and can stain the surface by spring.
2. Balance pH and alkalinity first.
3. Shock the pool. Pentair's guidance is to always shock before adding winterizing chemicals. If your closing kit includes an algaecide, follow its label on timing, since many tell you to let the chlorine drop first.
4. Run the filter for a day so everything is mixed and filtered.

Close the season with a clean filter so it does not sit all winter full of oils and debris. For a DE filter like the Pentair FNS Plus in our packages, backwash, then open the tank and hose off the grids. Pentair notes that the elements may need manual cleaning at winterizing. Drain the tank and leave the drain plug out. For a cartridge filter, remove the cartridges, clean them and store them dry indoors.

This depends on your pool type, and it is where people make expensive mistakes.

Fiberglass. Keep it nearly full. Lower the water only enough to clear the skimmer, or not at all if the skimmer is plugged, and follow your builder's instructions. Never drain a fiberglass pool. An empty or near-empty shell loses the weight that holds it down against groundwater. That matters here. Common Northeast Ohio soils such as the Ravenna silt loam, which the USDA describes as holding a perched water table 7 to 11 inches below the surface from October through June, stay wet all winter.

Vinyl liner. Lower the water to just below the skimmer, or below the return lines if that is how your plumbing is set up. Do not go further. The water holds the liner in place and protects it.

Concrete. Similar to vinyl: below the skimmer or returns, as your builder recommends.

Keep the water level up all winter. A pool that loses water to a leak can end up lower than it should, so glance at it a few times over the season.

This is the step that protects the most money. Water left in a pipe will freeze, expand and crack it, and in an inground pool those pipes are under the deck.

• Blow air through each line with a shop vacuum set to blow or a pool line blower, from the equipment toward the pool, until you see bubbles and then only air.
• Plug each return fitting and the main drain line as it clears. The main drain line is usually blown until bubbles appear at the drain and then valved off so the water in the pipe holds an air lock.
• Put a gizmo or winter plug in each skimmer. Pentair's winterizing guide describes this as the usual way to keep frozen water from damaging the skimmer and the pipe below it.
• Some owners add pool antifreeze to the lines after blowing them out. It is made for pools, not cars, and it is a belt-and-braces step, not a substitute for clearing the water.

Many owners hire this part out the first year. It is fiddly, and a missed line only shows up as a leak in spring.

• Turn off power to the pump, heater, lights and any automation at the breaker.
• Remove all drain plugs from the pump, filter and heater so no water is trapped inside. Store the plugs in the pump basket, as Pentair suggests, so they are easy to find in spring.
• Open the filter's air relief valve.
• Follow the heater's manual. Gas heaters and heat pumps each have their own draining steps.
• If your equipment is small enough and removable, some owners store the pump indoors. Most modern pads are plumbed in and stay put, drained.

A note on variable-speed pumps: many have a freeze protection mode that runs the pump when it gets cold. That is useful if you keep the pool running into late fall, but it only works while the pump has power and water. Once you winterize, the equipment should be dry and off.

More lines, more places for water to hide. A spillover spa has its own returns, jets and often a separate suction line, and each has to be blown out and plugged like the pool lines. Air blower lines for spa jets need clearing too. Heaters hold water in the heat exchanger, and gas heaters and heat pumps have different drain points, so work from the manual for your model. If your pad has automation, note the valve positions before you start. Getting them back in spring is easier with a photo on your phone.

A mesh safety cover anchored into the deck is the most common choice here. It holds weight, lets snowmelt and rain drain through and keeps children and pets out. A solid cover keeps the water cleaner because sunlight and fine debris are blocked, but water and snow collect on top and have to be pumped off. With a solid cover on an inground pool, Pentair suggests water bags around the edge to hold it down.

An automatic cover is designed for daily use in season and may or may not be rated for snow load. Check the maker's guidance before relying on it through an Ohio winter.

Whatever cover you use, check the barrier fence and gates once the pool is closed. The pool is still a drowning risk with a cover on, and a gate left propped open over the winter is easy to forget.

• Pump rain and melted snow off a solid cover so it does not sag into the pool.
• Brush heavy snow off gently if the cover maker recommends it. Lake-effect storms in Geauga and northern Summit County can pile up fast.
• Check that the water level has not dropped.
• Look at the equipment pad after a hard freeze for anything cracked or displaced.

Closing too early and opening to a green pool. Missing a return line so it cracks under the deck. Leaving a drain plug in the filter. Draining a fiberglass pool too far. Leaving the breaker on so the pump tries to run dry. Every one of these costs more to fix than a professional closing costs to book.

If you are comfortable with the equipment and have a way to blow out the lines, you can close your own pool. Many people do. If you are new to it, or you have a heater, automation or a spa, it is worth having a professional handle at least the first closing. We do closings and winterizing as part of our pool service, alongside openings, weekly cleaning and repairs. Some customers watch us once and take it over the year after.

Either way, write down what you did, what you plugged and where the parts went. In April, you will be glad you did.