What should I check first when uncovering my Ottawa pool after a long winter?

When uncovering your Ottawa pool after a long winter, the first thing you should check is the water level and colour beneath the cover — this tells you immediately whether you're dealing with a routine opening or a problem that needs attention before you proceed with any equipment start-up. A normal water level that has dropped only slightly (5 to 15 centimetres) with greenish but not opaque water means winter went well. A dramatically low water level, completely black water, or a strong sulphur smell all signal issues that change how you approach the rest of the opening.

A significant water loss over winter — more than 30 centimetres below where it was at closing — indicates one of three problems that must be diagnosed before you start the pump. The most common cause is a small plumbing leak that developed when winterization plugs shifted or loosened during freeze-thaw cycles. The second possibility is a vinyl liner tear or separation from the track, which can happen when ice sheets form on the pool surface and shift during winter temperature fluctuations. The third and most serious is a structural crack in a concrete or fiberglass shell caused by frost heave or hydrostatic pressure from Ottawa's high water table during spring thaw. In any of these cases, refilling the pool and starting the pump before identifying the source of the water loss can make the problem worse — a plumbing leak under pressure loses water faster, and a liner that's pulled away from its track can wrinkle or tear further if water pressure pushes against it.

After assessing the water level, check the winter cover itself for damage, sagging, or displaced anchors. Ottawa's winter puts extreme stress on pool covers — snow loads can exceed 120 kilograms per square metre, ice formation along the cover edges can pull anchor straps, and wind events can shift the cover position. Note any torn straps, pulled anchors, or holes in the cover material. A cover that has sagged significantly into the pool means the anchors or straps failed at some point during winter, and the cover may have allowed debris, animals, or contaminated meltwater into the pool. Document the damage before removing the cover — you may need this for a warranty claim, and knowing what failed helps you prevent it next season.

Before removing the cover, pump off any standing water on the surface of solid covers. Mesh covers drain naturally, but solid or hybrid covers can hold hundreds of litres of meltwater, dead leaves, and organic sludge that accumulated during the spring thaw. If you pull a solid cover without pumping it off first, all of that contaminated water — along with leaves, worms, insects, and whatever else collected over winter — dumps directly into your pool, dramatically increasing the chemical demand and filtration time needed to clear the water. A submersible cover pump costs $75 to $200 and is essential equipment for solid cover owners. Clear as much debris off the cover as possible with a leaf net before pumping to avoid clogging the pump intake.

Once the cover is removed, visually inspect the pool shell and waterline before touching any equipment. Walk the pool perimeter and look for cracks in concrete or fiberglass, liner separations along the top track, tile damage, and any staining or discolouration that wasn't present at closing. Ottawa pools are particularly susceptible to waterline staining from the tannins released by leaves and organic debris that sat on or near the waterline all winter, and to calcium scaling caused by Ottawa's hard municipal water. Note any staining patterns — a uniform brownish ring at the waterline is normal and responds well to enzyme and tile cleaner treatment. Irregular dark or rust-coloured staining suggests metal deposits (iron or manganese from Ottawa's water supply) that require a sequestrant treatment before you shock the pool or you'll set the stains permanently.

Equipment Inspection Before Start-Up

Check all equipment for visible freeze damage before reconnecting and starting anything. Even in a properly winterized pool, Ottawa's extreme cold can occasionally cause damage. Inspect the pump housing for cracks — hold it up to the light or run your fingers along the seams. Check the filter tank for cracks, and on sand or DE filters, check the multiport valve for damage. Examine the heater cabinet and look for signs of rodent nesting — mice and squirrels frequently move into pool heater cabinets over Ottawa winters because they're sheltered and insulated. Rodent damage to wiring, gas connections, or control boards is a common and potentially dangerous issue. If you see evidence of nesting, have a technician inspect the heater thoroughly before firing it up.

Reinstall drain plugs in all equipment before adding water to the system. During closing, drain plugs were removed from the pump, filter, heater, and chlorinator to allow trapped water to drain. These plugs were (hopefully) stored in the pump basket or taped to the equipment — check there first. If any plugs are missing, they're standard sizes available at any Ottawa pool supply store for $3 to $10 each, but do not start the pump without them or water will spray from the open drain ports, and the pump won't develop suction.

Remove all winterization plugs from the return fittings and skimmer before starting circulation. Starting the pump with winter plugs still in the returns creates a dead-head condition where the pump builds pressure with no outlet, potentially damaging the pump seal, cracking the filter tank, or blowing out plumbing fittings. This is one of the most common and avoidable mistakes during DIY pool openings. Count the plugs as you remove them and compare to the number that were installed at closing — a plug left in a return fitting that's submerged and hard to see can cause a pressure spike when the system starts.

Fill the pool to the proper operating level before starting the pump. The water level should be at the centre of the skimmer mouth — approximately halfway up the skimmer opening. Ottawa's municipal water supply will work fine for topping up; well water should be tested for metals first because iron and manganese levels in Ottawa-area wells can be high enough to stain pool surfaces when the water is shocked. Filling from the garden hose at a typical Ottawa water pressure takes 3 to 8 hours to raise the level 15 to 20 centimetres in a standard inground pool, and you should be present or checking periodically to avoid overfilling.

Finally, prime the pump before starting it. Remove the pump lid, fill the pump basket housing with water from the garden hose until it overflows, replace the lid and tighten the locking ring, and then start the pump. Watch the pressure gauge on the filter — it should climb to the normal operating range (typically 8 to 15 PSI for a clean filter) within 30 to 60 seconds. If the pump runs but doesn't prime — the basket stays empty and the pressure gauge doesn't rise — there's likely an air leak on the suction side, a blocked impeller, or a closed valve somewhere in the system. Don't let the pump run dry for more than 2 minutes, as this can burn out the mechanical seal and damage the motor. The cost to replace a pump seal is $150 to $300, and a burned-out pump motor runs $400 to $800 — both entirely avoidable by verifying proper priming before extended operation.