This one needs a licensed pro
Likely cause: a leaking tank joint or base seal. Call a plumber
Water at the tank bolts, the seam between tank and bowl, or the floor around the base points to a worn gasket, loose bolts or a failed base seal. A plumber should sort it out.
Why this happens
Korky says water leaking from the tank bolts or around the tank base means the tank to bowl gasket and hardware are worn, and that the tank bolts may loosen as the gasket compresses. Bob Vila says worn spud washers or crumbling bolt washers are common causes. This Old House says that if the leak is most prominent on the floor around the toilet, or on the ceiling below, the wax ring seal between the toilet and the flange may have failed, which means pulling the toilet.
What to do right now
- Turn off the toilet's own supply stop by hand. If it will not turn, do not force it. Shut off the main water supply instead, also without forcing it.
- Flush to drain as much water from the tank as you can. Korky says to do this right after shutting off the water, before you work on the tank and bowl joint.
- Mop up the water so no one slips and so it does not soak the floor.
- If you can see that the tank bolts are loose, Korky says tightening may fix it. Alternate sides as you tighten, which Korky says keeps the tank level and stable, and Korky suggests having a partner press down evenly on both sides of the tank while you do. Do not overtighten or let the tank touch the bowl, because the porcelain can crack. Then turn the water back on slowly, as Korky advises, and watch the bolts and the seam while the tank refills. If water still shows, turn the supply stop off again by hand and stop.
- Do not caulk around the base of the toilet to hide a leak. This Old House says caulk can mask an active leak and trap water underneath, where it keeps causing hidden damage.
- Keep the toilet out of use until a plumber has looked at it.
- Call a licensed plumber.
When to stop. If water is still coming out after the supply is off and the tank is empty, if the floor or ceiling below is wet or soft, or if you see a crack in the tank, stop and call a plumber right away. If water reaches an outlet, plug, cord, switch or light, including a light in the ceiling below, do not touch it and call an electrician, since Ready.gov says not to touch electrical equipment if it is wet or if you are standing in water.
What to tell the plumber
- Where the water starts: the tank bolts, the seam between tank and bowl, or the base of the toilet.
- Whether the leak happens when the tank refills after a flush, or only when the toilet is full.
- Whether the floor or ceiling below is stained or soft.
- Whether you tightened the bolts and by how much.
Build the full list: what to tell the plumber.
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