Pool pump freeze damage almost always means a cracked volute (pump housing), cracked filter housing, or burst plumbing fittings. Water expands 9% when it freezes and plastic components can’t handle that. Before assuming the pump is dead: confirm where the crack is and whether it’s in the pump body or just a fitting — a cracked fitting is a $5 fix, a cracked volute may mean a new pump.
Fill It Up and Look — The Pressure Test
Before ordering any parts, do a visual assessment with the system pressurized. Fill the pump strainer housing with water, seal the lid, and start the pump. Run it for 60 seconds while watching every component carefully. The crack will reveal itself as a steady drip or stream under pressure. Mark the location with a marker before shutting down.
In Arizona I don’t see freeze damage often, but I’ve been called to fix it in clients who have vacation properties in freeze climates. The damage pattern is always predictable: water trapped in the pump body or filter housing freezes, expands, and splits the casting along its thinnest walls — typically around the inlet port or along seam lines.
Galipp’s Gadgets replaces a pump cracked by a hard freeze — the same teardown you’ll do once you confirm the housing split.
What Typically Gets Cracked
Pump Volute (Wet End Housing) — Most Common
The volute is the spiral-shaped pump body that houses the impeller. It’s the water-containing part of the pump that sits between the motor and the inlet/outlet connections. Freeze cracks typically appear around the inlet port (where water enters from the skimmer) or at the drain plug holes at the bottom of the housing.
A cracked volute assessment: is it a hairline crack or a full split? Hairline cracks can sometimes be repaired with two-part epoxy as a temporary fix, but the repair rarely lasts more than one season. On a pump over 7 years old with a cracked volute, I always recommend replacement rather than repair. The wet end alone runs $80–180; a full pump replacement is $200–450.
Filter Housing — Second Most Common
Sand filter tanks, cartridge filter housings, and DE filter tanks are all vulnerable to freeze splitting. Filter tank cracks are typically more serious than pump cracks because filter tanks hold higher working pressure. Small cracks in plastic filter tanks can be epoxied for a season, but fiberglass filter tanks with structural cracks need replacement ($150–400 for the tank alone).
Plumbing Fittings and Unions — Free to $30 Fix
PVC fittings, union collars, and pipe sections that hold trapped water are the most vulnerable components. The good news: these are cheap and easy to replace. A cracked union is a $8–15 part. A cracked PVC fitting is $2–10 plus PVC cement ($6). Always check fittings before assuming the pump body is cracked.
Drain Plugs — Check These First
Most pumps have drain plugs at the bottom of the volute specifically for winterization. If the drain plugs weren’t removed before the freeze, the trapped water in the housing had nowhere to go. After a freeze event, always check drain plug threads for cracks even if the plug itself looks fine.
Repair vs. Replace Decision
Use this framework: if the pump is under 5 years old and only the volute is cracked, a wet end replacement ($80–180) makes sense. If the pump is 7+ years old, replace the complete pump and start fresh with a correctly winterized system. The motor is likely aging too and a new pump gives you a warranty starting from zero.
Repair vs. replace rule for freeze damage: Cracked fitting or union only (≤30 in parts) → always repair. Cracked volute on pump under 6 years old → replace wet end. Cracked volute on pump 7+ years old → replace full pump. Multiple cracked components → always replace full pump and fix all plumbing before winterizing properly.
How to Prevent Freeze Damage Next Season
The only reliable prevention is complete drainage. Remove drain plugs from the pump housing (there are two — one on each side of the volute bottom). Store the plugs in the strainer basket so you don’t lose them. Blow out the suction and return lines with a shop vac or compressor. Remove the filter drain plug. On equipment you can’t easily blow out, use non-toxic RV antifreeze (— automotive antifreeze is toxic to pool water and wildlife).
In climates that see below-freezing temperatures more than a few nights per year, automated freeze protection is worth installing: a freeze sensor connected to the pool automation system that turns the pump on automatically when temperature drops near freezing keeps water moving and prevents freeze damage without manual intervention.
Frequently Asked Questions
Can I use epoxy to fix a cracked pool pump housing?
As a temporary fix, yes. Two-part epoxy designed for wet surfaces (PC-7 or PC-11, $10–18) can seal hairline cracks and buy you a season. The repair typically doesn’t survive another freeze-thaw cycle. I’ve used it to get through the remainder of a swim season before a proper replacement — not as a permanent solution.
My pool pump cracked during a mild freeze — why?
It doesn’t take a hard freeze to crack a pump housing. Water begins expanding significantly as it approaches 32°F, and if the pump housing is already under slight stress from age or previous damage, even a brief freeze event can cause cracking. Pumps that have been improperly handled, dropped during installation, or are UV-degraded from years of sun exposure are more vulnerable to freeze cracking at temperatures that wouldn’t damage a newer unit.
The pool pump froze but still runs — is it damaged?
Possibly, subtly. Run it for a few minutes while watching for any new drips or seeps, especially around the drain plugs and along the volute seam lines. A pump that survives a freeze without visible cracking may have developed micro-cracks that don’t appear until the next heating cycle or when system pressure increases. Monitor it closely for the first few weeks after the freeze event.
Should I add antifreeze to my pool pump?
Non-toxic propylene glycol antifreeze can be added to pump housing and plumbing lines that can’t be fully drained. Use RV or marine antifreeze specifically — never automotive antifreeze (ethylene glycol), which is toxic to animals and pool chemistry. Add it through the skimmer with the pump off, enough to protect the lines to your expected low temperature.
How do I remove the pool pump drain plugs for winterization?
The two drain plugs are at the bottom of the pump volute — typically plastic square-drive or slotted plugs. Turn counterclockwise to remove. They should come out by hand with at most a slight assist from a screwdriver. Never use a wrench on plastic drain plugs — you’ll strip the plastic housing threads. Store them in the strainer basket so they’re with the pump when you reassemble in spring.