How to Stop Leaking Commodes

Before repairing, make sure that excess water isn't from condensation or "sweating."

The two most common toilet leaks occur at either the bottom of the toilet tank or underneath the toilet, due to a broken flange. A leak coming from underneath the toilet base is particularly damaging if not repaired quickly. The excess water can cause extensive floor damage over a fairly short period of time. Barring any floor damage which might require a professional renovator, an inexperienced but prepared homeowner can resolve both types of commode leaks.

Things You'll Need

• For leaks from the bottom of the tank:
• Anti-siphon ball cock
• Metal washer
• Rubber washers
• Teflon tape
• Wrench
• Braided stainless-steel line
• For leaks from the bottom of the toilet:
• Toilet flange
• Flange reinforcement ring
• Cloth rags
• Putty knife
• Hammer drill
• 1/4" masonry bit
• 2 sets of 5/16 inch diameter water closet bolts
• Silicone-based caulk

Instructions

Fixing a leak from the bottom of the tank

1. Shut the water supply off by turning the shutoff valve at the base of the toilet. Flush the toilet a couple of times to empty the tank.

2. Unscrew the supply-line coupling, detach the line, and unscrew the jamb nut that holds the ball cock in. Place a new washer over a new, anti-siphon ballcock (which prevents any waste-water backflow) and coat the washer with Teflon tape. Tighten the nut by hand, then finish with a wrench.

3. Loosen and remove the tank bolts with a wrench. Replace the old rubber washers that surrounded the bolts with new rubber washers. Place the bolts back in place and gently tighten them with a wrench.

   Do not over-tighten the bolts; you could crack the porcelain.

Fixing a leak from the bottom of the toilet base

1. Shut the water supply by turning the shutoff valve at the base of the toilet. Flush the toilet a couple of times to empty the tank.

2. Loosen the tank bolts inside the toilet tank to remove it from the commode base. Loosen the water closet bolts and nuts at the base of the toilet and gently lift the commode base from the floor. Set both tank and base to the side.

3. Push a rag into the exposed drain opening in the floor to prevent sewage gas from entering your home. Remove old wax and caulk around the drain opening with a putty knife. Finish cleaning the debris around the opening with mineral spirits and a rag.

4. Place the flange reinforcement ring over the toilet flange so that water closet bolt holes line up. Place the lined-up ring and flange around the drain opening and mark your screw locations on the floor through the bolt holes.

5. Drill holes into the marked spots with a hammer drill and 1/4-inch masonry bit until you reach the subfloor. Screw the new toilet flange into place around the drain opening.

6. Lay a line of silicone caulk around the opening of the new toilet flange and place the reinforcement ring on top of the flange so that the bolt holes line up.

7. Screw the reinforcement ring into the floor, place the water closet bolts--threaded ends facing the ceiling--into the slots of the flange and reinforcement ring. Remove excess caulk from around the flange and ring. Let the caulk harden overnight before placing the commode base back over the drain opening and newly set water closet bolts.

Tips & Warnings

• When repairing your toilet, try to avoid purchasing individual parts at the hardware store. Purchasing a toilet repair kit, specific to the type of repair you need to do, can save money and inconvenient trips back to the hardware store to buy parts you'd forgotten to get.

References

• This Old House: Fixing a Leaky Toilet
• The Family Handyman: How to Repair a Leaking Toilet