Risk of Water Damage

• Ignoring the water that you see leaking out from under the toilet bowl's base will lead to water damage to the bathroom and even other parts of the house. The finished flooring will eventually start to wear out or become stained from the exposure to water, especially if it is linoleum. The leaking water can enter the subfloor, leaking through the ceiling in the room below. Also, the water buildup in the subfloor can promote mold growth and rot away at the floor joists.
  
  

Flange or Wax Ring

• When a toilet starts leaking water from under the bowl's base, the culprit is either the wax ring or the flange. The wax ring and flange work together to make a watertight seal between the bottom of the toilet's bowl and the large drain pipe, called a soil pipe, in the bathroom's floor. It is impossible to tell whether it is the flange or the wax ring that has failed unless you unseat the toilet.
  
  

Fixing a Broken Flange

• When you remove the toilet, you must scrape off the old wax ring with a putty knife so you can see the flange. Even a hairline crack in the flange can allow water to trickle out, so look over the flange carefully for any damage. A damaged flange can be reinforced with a repair strap, which anchors into the floor like the flange and sits on top of the flange, restoring the flange to a working order again.
  
  

Placing the New Wax Ring

• For a wax ring to work correctly, it must be installed correctly, otherwise the wax ring will leak water in the near future. You can either press the wax ring onto the bottom of the toilet, around the opening called the horn, or directly onto the flange. Whichever mounting position you choose, the rounded side of the ring must touch the toilet's base and the flat side must touch the flange.
  
  

Proper Setting of the Toilet

• Setting the toilet the right way is the next step to guarantee the base of the toilet does not leak in the future. When you set the bowl over the flange and wax ring, you cannot rock or twist the toilet in any direction. Not tightening the nuts onto the bolts on the toilet's base enough will allow the toilet to rock, and the seal will break. Overtightening the nuts will crack the toilet's base. To avoid either pitfall, tighten the nuts until you feel resistance.