Stop the water first
Find the oval or round valve on the wall or floor behind the toilet. Turn it clockwise until it stops. Flush once to empty the tank. That stops a supply leak and keeps the bathroom from flooding while you look.
If that valve will not turn or keeps dripping, close the main water valve for the house instead. Do not force a stuck valve with a wrench, since it can snap.
Put towels down and wipe every surface dry. A dry toilet shows exactly where fresh water appears. Call (630) 822-9290 if water keeps flowing and you cannot stop it.
Find the leak by location
Dry the floor and the toilet, then wrap a strip of dry toilet paper around each joint. Wet spots show you the source. Check these in order.
| Where | Likely cause | Typical fix |
|---|---|---|
| Wall valve or supply line | Loose nut or worn washer | Tighten a quarter turn or replace the line |
| Under the tank | Worn tank to bowl gasket | Replace the gasket kit |
| Tank bolts | Worn bolt washers | Replace the bolts and washers |
| Base of bowl | Failed wax seal | Lift and reset the toilet |
| Inside bowl, no visible leak | Flapper not sealing | Replace the flapper |
Leaks at the supply line and valve
A braided supply line can be replaced in a few minutes. Shut the valve, disconnect the line at both ends over a towel, and install a new one hand-tight, then a quarter turn more. Over-tightening cracks plastic fittings.
If the leak is at the valve stem, tightening the packing nut a little may stop a drip. If the valve itself leaks when turned, it needs replacement, and that sometimes means shutting off the whole house.
Leaks at the tank and bolts
A leak under the tank usually comes from a worn rubber gasket between the tank and bowl. The fix is a gasket and bolt kit. Empty the tank, remove the bolts, lift the tank, and set the new gasket. Tighten evenly, alternating sides, and stop when snug.
Porcelain cracks if you overtighten. A hairline crack in the tank or bowl is not fixable with a patch. A cracked tank that weeps needs replacement, and a cracked bowl can fail without warning.
Condensation that looks like a leak
A tank that sweats in summer can drip onto the floor and look like a leak. Moisture from humid air condenses on the cold tank wall, runs down and pools. If the water is clear, shows up only in humid weather and every joint is dry, condensation is the likely cause.
Run a bathroom fan, dry the tank, and watch. If the floor stays dry for a day, you are probably fine. If water returns on a cool dry day, go back to the joint checks above.
The quiet leak: a flapper that does not seal
A toilet that refills by itself every few minutes has a flapper leak. Water slips from the tank to the bowl with no sign on the floor. It is the most common hidden toilet leak, and it raises your water bill.
Drop a few drops of food coloring in the tank and wait fifteen minutes without flushing. If color shows in the bowl, the flapper or its seat is leaking. Replace the flapper with the same type, and clean the seat with a cloth.
Using your Village water meter to confirm a hidden leak
The Village of Hoffman Estates bills water through its Water Billing office at 847-843-4824, and the system includes more than 15,000 meters. A silent toilet leak does not leave a puddle, so the meter is your most reliable witness.
Turn off every tap and appliance, read the meter, wait twenty minutes without using water, and read it again. If the numbers moved, water is leaking somewhere in the house. A moving meter with a dry toilet floor points to the flapper or another hidden leak. Call Water Billing with questions about reading your meter or bill, then call (630) 822-9290 if you want the leak found.
After you replace a flapper, check the fill valve and the chain too. A chain that is too tight holds the flapper open, and one too loose can tangle under it. Leave about a half inch of slack.
Leaks at the base of the toilet
Water around the base means the wax seal has failed or the toilet is loose. This can also mean the flange is damaged. Tightening the closet bolts a little can help on a loose toilet, but do not crank them.
If the leak returns, the toilet has to be lifted, the old wax scraped off and a new seal set. Anyone can do it, but a toilet is heavy and the opening needs to be covered during the work. A rotted floor or broken flange makes it a plumber's job.
Water at the base can be clean supply water or wastewater. If it smells like sewage, treat it as contaminated, wear gloves, and keep children and pets away. Call Call (630) 822-9290 before you touch it.
A reset toilet should be seated and sealed according to the Illinois Plumbing Code (77 Ill. Adm. Code 890). A soft floor or cracked flange gets repaired before the toilet goes back, not after.
What affects the price of a toilet leak repair
A leak can be one small part or a floor repair, so the work varies a lot. We give the price by phone after learning where it leaks, and we confirm before starting.
What changes the price
Ask whether the quote covers a new wax seal and bolts when the toilet is lifted. They cost little and are needed. Call (630) 822-9290 to describe your leak and get a price.
When to call a plumber
Call if the leak is at the base, if the floor is soft, if the tank or bowl is cracked, or if you cannot shut the water off. Call if there is any sewage smell. Call too if a leak returns after you replaced the obvious parts.
If water is coming through the ceiling below, close the main valve and call (630) 822-9290. If water is near outlets or a light fixture, keep away from the area. For related work, see toilet repair and installation. If a toilet backs up as well as leaks, our drain cleaning page explains what causes it. We also serve Schaumburg.
The Village Water Billing office at 847-843-4824 handles billing questions. A hidden toilet leak is a common cause, so check the meter test above first.
A flapper leak shows no water on the floor and the tank refills by itself. A wax seal leak leaves water around the base.
Not if it leaks at the base or the tank is cracked. Stop using it and shut the supply valve.
Yes, if moisture stays in the floor or wall. Dry the area quickly and watch for staining or a musty smell.
Sealants are not a lasting fix for toilets. They can hide a failing part until it gets worse.