How to fix a leaky base?
Lately you've noticed water near the base of the toilet.
This is usually a sign that the bowl wax gasket on the toilet flange has failed. But that's not always the case, and because fixing a broken gasket requires taking up the toilet, it pays to investigate the quick fixes. Often, water that appears on the floor is not bowl but tank water. If the tank has been bumped, it's not uncommon for water to leak past the tank bolts, dripping to the floor. Reach under the tank, and feel for moisture clinging to the tank bolts. If the bolts are wet, dry them using a paper towel. (Although a disturbed tank bolt may leak persistently, sometimes one bump makes one drip, and that's it.
After an hour or so, check the bolts again.If they're wet, you have a tank leak. Carefully tighten the nus on the tank bolts a half-turn to a full turn to stop the leak. If the leak persists, then tighter the nuts one or two turns. If the leak still persists, remove the tank bolts and install new bolt washers. In this case, you usually will not need to disturb the tank-to-bowl seal or the water connection. Just turn off the water from the tank. Then remove the bolts; replace the washers; coat them liberally with pipe joint compound; and reinstall the bolts.
If the tank is not leaking, the problem is with the wax gasket in the toilet flange. You'll have to take up the toilet and replace the seal.