Hot tub leaking
Quick answer
Most hot tub leaks are in the plumbing, not the shell: loose unions at the pump and heater, a worn pump seal, cracked fittings, or jet gaskets. Find it by letting the water drop to the leak level and looking for the wet spot under the cabinet. Small plumbing leaks you can often tighten or seal; a cracked shell or a failed pump is a pro job. A pour-in sealer is a last resort for a weep you cannot locate.
Water dropping faster than evaporation explains means a leak somewhere, and the good news is that the common ones are at accessible plumbing joints, not the tub body. Find where it is first, then decide what to do.
Find the leak first
- Let the water find its level. Stop topping up and let it drop until it stops. Where it settles tells you the height of the leak, often a jet or a fitting at that line.
- Open the cabinet and look. With a dry paper towel, trace the wet path back to its source. Run it with the pump on and again with it off, since some leaks only weep under pressure.
- Check the usual suspects. The union nuts on the pump and heater, the pump shaft seal, the heater ends, jet bodies and their gaskets, any gate or slice valve, and the drain spigot. These cover the large majority of leaks.
Switch off at the breaker before working in a wet equipment bay, since water and mains power do not mix. Leave a leaking pump, heater, or any electrical part to a qualified technician.
What you can fix yourself
- Snug a loose union. A union nut at the pump or heater often just needs hand-tightening. Do not overtighten or use tools that can crack the plastic; firm by hand is usually enough.
- Replace an o-ring or gasket. A weeping union or jet often just needs a new o-ring, a cheap part once you have the size.
- A pour-in sealer for a hidden weep. For a small, slow leak you genuinely cannot find, a spa leak sealer circulated through the system can seal it from inside.
What needs a pro
A cracked shell can sometimes be patched with an acrylic repair kit, but matching and a lasting bond are hard, so it is usually a professional job. A leaking pump (water from the seal or wet end) needs the seal or pump replaced. And in a full-foam cabinet, a pipe leak buried in the foam has to be dug out and repaired, which is firmly technician work. Pour-in sealers are a gamble on these, not a fix.
What helps
For a small, slow leak you cannot locate, a pour-in spa leak sealer is the honest last resort. For a visible loose union, a fresh o-ring and hand-tightening fix it for nothing.
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Common questions
Where do hot tubs leak most often?
At the plumbing rather than the shell: the union nuts at the pump and heater, the pump shaft seal, jet bodies and gaskets, and slice or gate valves. Letting the water drop to its leak level and tracing the wet path under the cabinet usually finds it quickly.
Do hot tub leak sealers actually work?
For small, slow leaks they can, by sealing the gap from inside as the water circulates past it. They are a reasonable last resort for a weep you cannot find or reach. They are not a fix for a visible loose union, a cracked shell, or a leaking pump, where the real repair is the right move.
How much water loss is a leak versus evaporation?
Evaporation and splash-out cause some normal drop, more in cold weather and with frequent use. If you are topping up well beyond that, or the water keeps dropping to a particular level and stops, that is a leak at that height, not evaporation.