The short answer
Water around the base of a toilet in a Northern Virginia home comes from one of four places, and only one of them is the wax ring under the toilet. The other three drip down from higher up and pool at the base: sweat off the tank, a supply line or shutoff valve, or the bolts between the tank and the bowl. Water that seeps out from under the edge of the toilet right after a flush is the wax ring. That one is worth fixing this week, because every flush sends dirty water into the floor.
Find where the water starts
- Dry the floor, the base, the tank and the supply line completely with a towel.
- Lay dry paper towels around the base, and tuck one under the tank and one under the supply line.
- Put a few drops of food coloring in the tank, wait five minutes, then flush once.
- Look at the paper towels. Colored water under the tank or the back of the bowl is tank water. Clear water along the supply line is the line or the valve. Water that shows up only at the front or sides of the base, right after the flush, is the wax ring.
- Beads of water all over the outside of the tank, with nothing else wet, is sweat, not a leak.
Swipe to see all columns →
Swipe to see all columns →
| Where it’s wet | When | Usually | What it takes |
|---|---|---|---|
| Under the edge of the base | Right after a flush | The wax ring, often because the toilet rocks | Pull the toilet, new wax ring, check the flange |
| Under the tank, at the back of the bowl | After a flush, or all the time | The tank bolts or the gasket between tank and bowl | New bolts and gasket |
| Along the supply line | Any time | The nut, the line, or the valve on the wall | A snug quarter turn, or a new line or valve |
| The whole tank is beaded | Humid days | Cold water in the tank sweating | Not a leak |
| A steady seep from one spot on the porcelain | Any time | A hairline crack | A new toilet |
If the water is coming from the tank, toilet tank leaking goes through the bolts, the gasket, the supply line and the valve one at a time.
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What the wax ring does
Under every floor-mounted toilet is a drain pipe that ends in a flange, a ring fastened to the floor. The toilet sits on it, and a thick ring of wax between the two makes the seal. It keeps the water from a flush in the pipe and the sewer gas out of the bathroom. Wax doesn’t wear out sitting still. It fails when the toilet moves. A toilet that rocks even a little breaks the seal a bit more every time someone sits down, and once it’s broken it doesn’t seal back.
The other common cause is height. When new tile or a new floor goes in and the flange stays where it was, it ends up under the finished floor and the wax can’t fill the gap. Stacking two wax rings is the usual shortcut and a common repeat leak. A flange extender, or a new flange set at the right height, is the fix that lasts. Wobbly toilet covers the rocking, the shims and the flange repair.
Signs it’s been leaking a while
- The floor feels soft or gives a little next to the toilet.
- Vinyl lifting or grout darkening around the base.
- A brown ring on the ceiling under the bathroom.
- A sewer smell in the bathroom with no clog. A broken wax seal lets sewer gas through, and sewer smell in the house covers the other places that smell comes from.
Can you do it yourself?
Pulling a toilet to change the wax ring is a job plenty of people do themselves. Turn off the valve behind the toilet, flush and sponge out the tank and bowl, unhook the supply line, take the nuts off the two bolts at the base, and lift it straight up. It’s heavier and more awkward than it looks, often 60 pounds or more. Scrape off the old wax, set a new ring and new bolts, lower the toilet straight down, and tighten the nuts a little at a time, side to side. Too tight cracks the porcelain.
Call instead when the shutoff valve won’t close or drips once you turn it, the flange is broken or rusted through, the floor around the drain is soft, or the toilet still rocks once it’s back down. Those are the jobs where a second try costs more than the first.
About caulk
Caulk around the base is fine for looks and keeps mop water out. It isn’t a fix for a leak. Leave a gap at the back so a future leak shows on the floor instead of hiding under the toilet.
A base leak is quiet. If the toilet is also hissing or refilling on its own, that’s a separate part, and what each toilet noise means sorts it out.
A wet floor at the toilet is one of the early ones. Every warning sign around the house, from a furnace’s blinking light to the sounds a house makes, is in one guide.
Fix it small, fix it now
A leak caught early is cheaper three ways. The water and sewer bill stops climbing. The water stops soaking the subfloor or the ceiling under it. And it stays a small repair, a part and an hour, instead of a bigger one later. Almost everything we find wrong with a toilet is repairable, and once it’s fixed right, you stop checking the floor every time you walk in.
What it costs when we fix it
Most leaks, wobbles and fill problems are a repair, toilet repair at $250 to $900, with the price in writing before we start. That covers a wax ring, a flange repair, tank bolts and gaskets, and fill valves. When the toilet itself is cracked or worn out, a new one installed runs $800 to $1,300, and this month’s coupons on our offers page take $100 off a new toilet, or $50 off any plumbing repair over $400. Any plumbing repair also comes with a whole-house plumbing inspection, a $149 value. If you can’t tell where the water is coming from, leak detection runs $200 to $500. A plumbing diagnosis visit is $49, or $250 after hours.
Call (703) 997-9757, day or night, or book a toilet repair online. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
Why is my toilet leaking at the base?
Most often the wax ring under the toilet has broken its seal, usually because the toilet rocks. Water dripping from the tank, the supply line or the valve can also pool at the base, so dry it and trace it first.
How do I know if my wax ring is bad?
Water seeps from under the edge of the toilet right after a flush, the toilet rocks, the floor next to it feels soft, or the bathroom smells like sewer gas with no clog.
Can I just caulk around a leaking toilet?
No. Caulk hides the leak and traps the water under the toilet. The wax ring has to be replaced. Caulk is fine afterward, with a gap left at the back.
How long does a wax ring last?
It can last as long as the toilet if nothing moves it. It fails when the toilet rocks, gets bumped loose, or sits on a flange that’s too low.
How much does it cost to replace a toilet wax ring?
When we do it, a wax ring is a toilet repair, $250 to $900, priced in writing before we start. A broken flange is fixed in the same visit.
