Answer first: Air escaping through a fitting or a sticking valve is a repair, usually $200 to $500. Water inside a cracked or seamed tank is a different problem: the blower cannot chase weight the way it chases missing air, so dry venting will not fix a wet tank. If your lift's low corner does not move regardless of how long the blower runs, you are almost certainly shopping a retank, not a valve job. Get every tank checked before paying for either.
Two tank problems that feel the same at the helm
| What you notice | Likely mechanism | Fix |
|---|---|---|
| Lift settles a little lower over days or weeks, blower brings it back | Slow air leak at a fitting, seam, or valve | Seal, valve, or fitting repair, commonly $200-$500 |
| Lift sits low and stays low no matter how long the blower runs | Tank has taken on water through a crack or failed seam; it is carrying weight, not just short on air | Retank, quoted by tank count and access |
| Boat sits crooked, one side worse than the other | One tank failing while its neighbors still hold | Usually a single-tank retank; check the others while access is open |
| Frame flexes, bolts loose, rust at the mounts | Frame problem riding along with the tank problem | Frame repair first; a new tank on a bad frame is wasted money |
How to tell air loss from a waterlogged tank
The two problems get confused because both show up as a lift that will not sit level or will not reach full height. The test that separates them is simple and does not require opening anything. Run the blower a full cycle and mark the waterline on the low corner. An air-loss tank drifts back down over the following days as the missing air re-vents; the blower fixes it again, temporarily, every time. A waterlogged tank does the opposite: it stays exactly where it settled, blower cycle or not, because the extra weight sitting inside it is water, and no amount of pumped air moves water out through a sealed tank fitting.
A soapy-water spray on the hose connections and valve fittings is the standard way to spot an air leak directly: bubbles forming under load mean air escaping there. No bubbles anywhere on the fittings, combined with a corner that will not respond to a full blower cycle, points at water intrusion instead, usually through a hairline crack or a failed seam on an older tank.
Why tanks fail on this lake
Tank construction has changed the failure pattern over the years. Modern air-tank lifts use tanks rotationally molded as a single sealed piece of polyethylene, with no seam to fail. One Camdenton-based lift manufacturer building this way since 1984 backs those seamless tanks with a lifetime warranty for the original owner, because a one-piece tank with no joint rarely springs a leak from ordinary age. Older lifts, and lifts built from multi-piece or bonded tanks, do not get that benefit: the seam is exactly where years of sun, freeze-thaw cycling, and flexing under load eventually let go.
Practically, that means most of the retanks we see fall into one of two buckets: an older-generation tank finally failing at a seam after a decade or two of service, or a newer seamless tank damaged by something specific, ice pinning the lift over a hard winter, a direct impact, or a puncture from debris. Neither one is a sign of a bad lift. It is a sign that the tank generation on that particular lift has reached the end of its run, or took a hit it could not shrug off.
The retank-vs-replace decision
The frame decides this, not the tank. Galvanized steel generally outlasts its tanks by a wide margin, so a straight, well-mounted frame with sound bolts and a motor that still has years left is the case for retanking: replace the failed tank or tanks, leave the rest of the lift alone, and the boat is back on a lift that is good for another decade or more. A frame that is rusted through at the connection points, or a motor and valve set that is also on its last legs, changes the math; putting new tanks under a failing frame is spending real money to delay a replacement that is coming anyway. We look at the frame and the mounts every time we look at a tank, and we say so either way.
Cost is priced by tank count and access, the same as every other job on this site: no fixed number until someone has looked at your lift, in writing before work starts. Full lift replacement, when the frame calls for it, runs $1,000 to $8,000 and up by capacity; the cost guide has the full breakdown next to every other repair on the lake. If the lift is bolted to a dock that has its own problems, worth a look at the same visit; lift symptoms and dock symptoms travel together more often than owners expect. If you are not yet sure the tanks are the problem at all, start from what the lift does when you press the switch.