Toilet tank overflowing
January 25, 2011 7:18 PM   Subscribe

Toilet problem: Water is overflowing in the tank (not the toilet bowl). Tried replacing the fill valve in the tank and thought it was fixed because it seemed the commode stopped running at the correct water line in the tank but the water keeps raising slowly until it overflows. Anybody know what the problem may be and how to fix?
posted by sandyp to Home & Garden (11 answers total) 1 user marked this as a favorite
did you replace the float?
posted by HuronBob at 7:23 PM on January 25, 2011

Sounds like the pressure switch that stops the inflow of water is borked. To fix? Replace that switch. Sometimes is a little float that goes up and down the shaft, sometimes it's a stationary piece and the pressure switch is on the underneath. Figure out which it is, go get a new one at the plumbing store / Lowes / Home Depot, and put it in. For bonus, either take good pictures and or take the piece out and take it to the store and they can match things up.
posted by deezil at 7:25 PM on January 25, 2011

Did you take the lid off and watch what is happening? Sometimes you can bend the shaft on the float downward, so that the shut-off is triggered sooner and/or more forcefully.
posted by StickyCarpet at 7:25 PM on January 25, 2011

Let me re-phrase that...

When you say "overflows" you mean into the overflow tube and into the bowel? If that's the case, I suspect the float needs to be replaced or adjusted.
posted by HuronBob at 7:26 PM on January 25, 2011

a combination of a plugged overflow tube (unless that's what you meant by overflowing), and a junk shut-off valve. In one place i lived, the valve kept getting plugged with solder from some new plumbing work that had been done. The design of the valve allowed it to be disassembled and cleaned out.

replacement assembles are ~$15 at walmart, and aren't that difficult to replace. in the meantime there should be a valve somewhere in the vicinity that supplies the toilet.
posted by ArgentCorvid at 7:38 PM on January 25, 2011

I had this problem recently. I live in an apartment, so I just put in a maintenance request and they fixed it, but the piece of paper I have says they "replaced ballcock kit."
posted by J. Wilson at 8:30 PM on January 25, 2011

If she's already replaced the fill valve then that's taken care of the float.

I've got to replace the fill valve on my guest bathroom toilet this weekend. Toiletology is an annoying website, but the information contained therein is good. There's a couple of troubleshooting pages that might help.
posted by elsietheeel at 10:00 PM on January 25, 2011

If she's already replaced the fill valve then that's taken care of the float.

Unless it's an old-style fill valve with a separate float that can get waterlogged and sink, which sounds like what's happening here. In that case, the float needs to be replaced.
posted by exphysicist345 at 10:13 PM on January 25, 2011

Try and break the diagnosis down into simple, easily answerable questions.

Overflowing into the overflow tube is definitely a fill valve-related problem. You don't need to look at other parts.

You know that part of the valve assembly is supposed to float. Is it floating? If not, why not? Is it hitting or snagged on something else in the tank? If so, adjust the positioning of various parts to eliminate the interference. Is the float itself leaky/waterlogged? If so, replace the whole valve assembly unless it's an old-fashioned ballcock with the float on a long wire across the top of the tank, in which case you can replace just the float.

If the float is floating, does the water shut off if you pull up on the float? Yes? Then read the valve instructions and figure out how you're supposed to adjust the water level so you can set it appropriately (mechanical designs vary). If pulling up on the float doesn't shut the water off, or if you have to apply a lot of upward force to get it to shut off, then something is wrong with the valve. It could be defective, or it could have a bit of debris stuck inside it. You can't know which without disassembling it, which might not be worth it if you can just exchange it for a new one.
posted by jon1270 at 2:22 AM on January 26, 2011

Not clear if you just replaced the existing parts or put in a modern fill valve (or started with one). Korky makes a good one. To adjust you basically empty the tank, loosen the plastic valve base, and make a couple of half turns to the mechanism so that the float stops where you want it to. These work much better than the old-style ones with a big ball float (although you can adjust those, too, if you understand how the screw works).

In any case, the basic idea is that an overflow inside the tank means you have the fill valve adjusted incorrectly. Find out how to adjust what you have, or replace it with something better.
posted by dhartung at 11:44 PM on January 26, 2011

Response by poster: Update: the fill valve was defective, it had a leak and the reason my commode tank was overflowing was because the overflow pipe was not proper height, it was close to the tank lid hence the water running over problem.
posted by sandyp at 7:17 PM on March 13, 2011

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