Toilet Leaking at Base
Updated February 20, 2026
Water pooling at the base usually means a failed wax ring. Left unaddressed: sewer gas in the home, subfloor rot, mold, and structural damage beneath the floor.
Overview
Water on the floor has passed through or around the wax ring connecting the toilet to the drain. Wastewater seeping onto the subfloor with every flush. Subfloor softens, mold grows where you cannot see it, structural integrity compromised. Fix: replace the wax ring. Remove toilet, scrape old wax, new ring, reset. 1-2 hours, under $25 in parts. Toilets are heavy (50-100 lbs).
Symptoms
- Water on the floor around the base, especially after flushing
- Toilet rocks or wobbles -- seal may already be broken
- Sewer smell that was not there before -- wax ring letting gas escape
- Discoloration, soft spots, or warping in the flooring around the base
- Stains on the ceiling below a second-floor bathroom -- leaking through the floor
- Caulk around the base discolored, cracked, or separating
Common Causes
- Failed wax ring -- thick wax ring seals toilet horn to the floor flange. Fails from age, movement, or temperature changes that harden and crack the wax.
- Loose closet bolts -- toilet shifts with use, breaks the seal. Even slight movement compromises it.
- Cracked base -- impact, overtightened bolts, or defect. Hairline crack leaks directly onto the floor. Requires toilet replacement.
- Damaged flange -- cracked, corroded, or below finished floor level. Wax ring cannot seal. Cast iron flanges in older homes especially prone.
- Condensation (false alarm) -- cold water causes condensation on the porcelain in humid weather. Drips and pools at the base. Wipe dry, check if moisture returns without flushing.
What You'll Need
How to Fix It
-
Confirm the Leak Source
Dry everything thoroughly. Food coloring in the tank, 30 minutes, no flush. Color at the base? Leak between tank and bowl or supply connection, not the wax ring. Dry until you flush, then water appears? Wax ring. Feel the outside for condensation.
Tip: Only during flushing? Almost certainly wax ring. Constant drip without flushing? Supply line or tank-to-bowl bolts first. -
Gather Supplies and Shut Off Water
New wax ring, new closet bolts, putty knife, wrench, towels, bucket, sponge. Water off, flush and hold the handle to drain. Sponge remaining water from tank and bowl.
Tip: Flange below finished floor level? Extra-thick wax ring. Or try wax-free (Fluidmaster Better Than Wax) -- reusable and adjustable. -
Remove the Toilet
Supply line disconnected. Decorative caps off, nuts off the closet bolts (hacksaw if corroded). Rock gently to break the old seal, lift straight up. 50-100 lbs -- lift with your legs, helper if possible. Set on a towel. Rag in the drain hole to block sewer gas.
Warning: Never leave the drain hole open. Methane and hydrogen sulfide are hazardous in enclosed spaces. Damp rag in the flange opening. -
Inspect the Flange and Clean the Surfaces
Scrape all old wax off flange and toilet horn. Inspect the flange: firmly anchored, at or above floor level? Cracks, corrosion, broken bolt slots? Cracked but anchored? Repair ring ($5-10). Severely corroded or broken? Full replacement -- plumber if not comfortable with drain work.
Tip: Check the subfloor for soft spots, discoloration, mold. Spongy or damaged? Repair before resetting. Rotted subfloor will not hold the toilet and the new seal will fail. -
Install the New Wax Ring and Reset the Toilet
New closet bolts in the flange slots, evenly spaced. Wax ring centered on the flange (horn pointing down if it has one). Remove the rag. Lift toilet, lower straight down, align bolt holes. Press down firmly with body weight -- do not rock or twist. Sit on it for a minute to compress fully.
Warning: One chance. Once the wax compresses, lifting and repositioning compromises the seal. Align carefully before lowering. -
Secure, Reconnect, and Test
Washers and nuts on the bolts. Tighten alternately, a few turns per side. Snug, not overtight -- porcelain cracks. Wobbles? Plastic shims. Reconnect supply, water on, flush several times, check for moisture. Dry? Trim bolts, caps on, caulk the base but leave the back uncaulked.
Tip: Back uncaulked on purpose. If the ring fails again, water escapes through the gap and alerts you instead of silently rotting the subfloor.
When to Call a Pro
Call a plumber if the flange needs full replacement (drain pipe work), if the subfloor is rotted, if the base is cracked and needs a new toilet, if you cannot lift it safely, or if the leak persists after a new wax ring. Plumber can also install a flange extender for raised floor levels.
Prevention Tips
- Never rock or lean hard on the toilet. Lateral movement is the number one cause of wax ring failure.
- Check closet bolts yearly. Gentle rock test -- any movement, tighten before the seal breaks.
- Wobbles? Shims immediately. Do not ignore it.
- New flooring? Adjust flange height to sit at or above the new level. Recessed? Extra-thick ring or extender.
- Caulk the base (back uncaulked for leak detection). Prevents water seeping under from mopping.
- Sewer smell that was not there before? Investigate immediately. Odor often comes before a visible leak.