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Speed matters. A small leak can wash out the soil under a liner or around a shell, a pump that runs dry can overheat, and a heater fault can involve gas or electricity. This page covers the warning signs, telling evaporation from a leak, liner and shell repairs, equipment failures, skimmer and winter damage, whether to drain the pool, and when repair turns into renovation.
Signs your pool needs repair: water loss, air in the pump and wet ground
Some problems are obvious; others show up as small changes over a week or two. Call a technician when you notice any of these.
- A water level that keeps dropping between top-ups, even in cool, cloudy weather.
- Air bubbles in the pump basket or spitting from the return jets.
- Soft, wet or sinking ground near the pool, the equipment pad or the pipe runs.
- A pump that hums, trips the breaker or runs hot, or a filter gauge that reads far from its usual pressure.
- Liner wrinkles, bulges or a liner pulling out of its track.
- New cracks, hollow spots or loose tiles on a concrete or fibreglass pool.
- A heater that won't light, shuts off early or leaves soot or scorch marks.
Finding a pool leak: evaporation vs leak and the bucket test
Every outdoor pool loses water to evaporation, splashing and backwashing, and more on hot, windy days. A bucket test tells the two apart: set a bucket of pool water on a step so its water line matches the pool's, mark both levels, and compare them a day later with the pump running as usual. If the pool has dropped clearly more than the bucket, something is leaking.
Repeating the test with the pump off narrows it down. A bigger loss with the pump on points to the plumbing, while a steady loss either way points to the liner, shell or fittings. Technicians then use dye near suspect spots, pressure tests on individual lines and listening equipment to find the leak before anyone cuts into the deck.
- Common leak points: the skimmer, return fittings, lights and their conduits, main drains and the joints at the equipment pad.
- Look at the equipment pad first: a dripping union, valve or pump seal is the easiest leak to fix.
- Mark the water level with tape and note every top-up, so the technician can see how fast it drops.
Liner, fibreglass and concrete pool repair vs pool renovation
A repair fixes one defect; a renovation replaces a worn surface or component across the whole pool. The line depends on the pool's age, how widespread the damage is and whether you are patching the same problem every season. Liner replacement, resurfacing, new coping and decking are covered on the pool renovation page.
- Vinyl liner: small tears and pinholes can be patched, often underwater, but a brittle, faded liner with several tears is usually due for replacement.
- Fibreglass: surface cracks and blisters are repaired and refinished to match, while a structural crack or a shifted shell calls for checking the base and backfill first.
- Concrete: hairline cracks in the finish are cosmetic, but cracks that leak, grow or run through the structure need a structural repair, often before resurfacing.
- Above-ground walls: rust-through, bulging or a sagging top rail on an older pool often means replacing the pool rather than repairing it.
Pool pump, filter and heater repair: common failures and who fixes them
Circulation equipment runs all season, and most failures show up at start-up or in midsummer heat. Motor and wiring faults go to a licensed electrician. Gas heater repairs go to a licensed gas technician: a fuels contractor registered with the TSSA in Ontario, or a contractor holding the appropriate RBQ gas licence in Quebec. If you smell gas near the heater, leave the area and call your gas utility from a safe place.
- Pump: a motor that hums without turning, trips the breaker or overheats, a leaking shaft seal, a cracked lid or housing, or air leaks that stop it from priming.
- Filter: a cracked tank, a torn cartridge or broken internal parts that let debris back into the pool, or pressure that stays high after cleaning.
- Heater and heat pump: ignition or sensor faults, a unit that runs without warming the water, or scale and corrosion from poorly balanced water.
- Valves and controls: stuck valves and failed timers or automation that stop the pump from running on schedule.
- Electrical warning signs: a tingle in the water or a breaker that keeps tripping means everyone out and a call to the electrician.
Skimmer and return fitting repair, and fixing winter freeze damage
Skimmers and return fittings sit where the plumbing meets the pool wall, and frost in the ground and ice in the water put them under stress. A cracked skimmer body, a loose faceplate or gasket, or a cracked return fitting tends to leak slowly, often just below the waterline.
Freeze damage is the other spring surprise: water left in a line, pump or heater expands as it freezes and splits it. Exposed pipes and equipment are simple to replace, but a cracked line under the deck may mean cutting into concrete or pavers, so its location is confirmed with a pressure test first. Book these repairs before the season starts, and treat a thorough fall closing as the prevention.
- A small skimmer crack can sometimes be sealed; a badly cracked skimmer on an inground pool is replaced by opening the deck around it.
- Gaskets and faceplates are routine replacements, usually done with the water lowered just below the skimmer.
- Photograph winter damage before the repair, in case your warranty or home insurance applies.
Should you drain a pool for repairs? Groundwater and the risks of emptying
Many repairs are done with water in the pool: liner patches, fitting replacements and some crack repairs can be made underwater or with the level only partly lowered. Draining is a professional decision, because the water holds a liner in place and balances a shell against the soil around it. Where groundwater is high, an empty fibreglass or concrete pool can be pushed upward, and an empty liner can shrink, shift or tear.
When a pool has to be emptied, for a new liner, resurfacing or a structural repair, the technician checks groundwater conditions first and plans the work so the pool sits empty as briefly as possible. Ask your municipality where the water may be discharged, since the rules for storm drains, sewers and neighbouring lots vary.
Pool Repair: frequently asked questions
Why is my pool losing water?
It may be evaporation, especially in hot, windy weather, or a leak. A bucket test compares the pool's loss with a bucket of pool water beside it; if the pool drops clearly faster, have a technician check the equipment pad, skimmer, fittings and liner or shell.
Can a pool liner be patched underwater?
Small tears and pinholes often can, with a patch made for underwater use, which avoids lowering the water. Long tears, seam failures or a liner that is brittle with age usually call for replacement instead.
Why won't my pool pump prime?
Usually air is getting in on the suction side: a low water level, a clogged skimmer or pump basket, a loose lid or worn O-ring, or a cracked fitting. If it still won't catch after those checks, switch it off so it doesn't run dry, and call a technician.
Is it worth repairing an old pool heater?
It depends on the fault and the heater's condition. A failed sensor or igniter is a routine repair, while a corroded heat exchanger on an older unit often points to replacement. Any gas work must be done by a licensed gas technician, and electrical work by a licensed electrician.
Sources
Written by the LokalMatch editorial team. Reviewed by Zubair Afzal on September 10, 2026. How we write and check our guides