A leak can occur anywhere water enters or leaves your home; do you know how to spot a leak and pinpoint the problem?  Some leaks may be solved with basic do-it-yourself techniques but others will require a professional plumber to handle.

First, check any visible pipes.  This includes pipes in the basement, behind washers, and leading to your water heater. Do you see any rust, drops of water, or buckling? These are all signs of a problem.  Wipe all sides of pipes with a dry tissue to check for any drops that may not be visible; a towel can hide small drops of water.

Check the base of your water heater. If there is any water leaking, it’s likely that the lining has worn away the entire heater will need to be replaced.  There’s no way to repair a leaking water heater. Ensure your new water heater has a pan installed under it to protect the floor.

Next, look inside cabinets in kitchens and bathrooms to find any leaks that will destroy cabinets, countertops, and eventually floors and subfloors. Remove everything you store in the cabinet so you can see signs of leaks. Do a visual check for:

  • Water drops, rust, or buckling on the pipes
  • Water stains, damp smells, mold, or puddles on the cabinet backs, sides, and bottom
  • Swollen particleboard under countertops
  • Loose or damaged floor in front of the cabinet

Check countertops for loose laminate, swollen particleboard, loose faucets, or deteriorating caulk.  If the faucet base is loose, tighten the mounting nuts underneath the counter.  Check to see if the clips under the sink rim are loose and tighten them. Re-caulking also helps stop water damage.

Most of us don’t peek in the shower unless we’re using it or cleaning it, which makes it difficult to notice leaks.  Check several hours after the water’s been turned off to see if the faucet or the shower head are leaking. If it’s the shower head, you may be able to fix a leak by either tightening it or removing it and re-installing it with plumber’s tape. A leaking shower faucet will need to be looked at by a plumber.

Check around your toilets.  Look for water seeping out of the base of the toilet or for damaged flooring. Push slightly on the toilet to be sure it doesn’t move. A leaking toilet will break the wax seal between the toilet and the floor, and eventually destroy the flooring around it.

Some of the leaks that are easily fixed include loose pipe connections that just need to be tightened or leaking washers in faucets. Other leaks, including toilets and shower faucets, need to be fixed by a professional plumber. 
With leaks, it’s better to be safe than sorry.  A small leak can cause major damage that will cost significantly more than having a plumber make a service call. Check all of your water entry and exit points every few months to avoid potentially costly problems.

Sources:
http://www.familyhandyman.com