It may seem that faucet leaks are obvious to spot but leaks can start in numerous ways and they can appear in more places than just at the spout. We recommend checking leaks in three locations.
Leaks from Spout
This is where faucet leaks are most obvious and visible. The faucet will start dripping or running. You may notice that after someone uses the faucet you have to go back to tighten it or get it in the right position, so it does not leak. A small drip will get worse over time and eventually add up on your water bill. To test if leak is coming from faucet, ensure sink basin is dry and place a paper towel under the spout and check back later to see if it wet. If the faucet leaks at the spout you might need to change the washers on the faucet or replace the faucet cartridge
to repair the leak.
Leak Around the Base of the Faucet
A leak around the base of the faucet is not quite as obvious. People wash their hands and then turn the faucet off usually leaving the water to drip on the handle and around the top of the faucet and sink area. This makes a leak hard to identify because of the excess water. If this area of the faucet leaks it will usually only be when the faucet is turned on. To check for a leak at the base of the faucet you will need to start by drying up all of the standing water. Then turn both handles on (or if it is a single handle faucet turn it in both directions) and see if water leaks around the faucet or at the top of the sink area. A leak like this will usually be caused by a dried-up o-ring or a worn out stem or cartridge. To repair the leak you can change the o-ring, stem or cartridge.
Leak Under Sink
A leak under the faucet can be the hardest to notice since it is out of sight. If you suspect a leak under the sink it is a good idea to locate leak and repair it immediately, to avoid water damage or further deteriorating pipes which can be costly to repair. Start by taking everything out from under the sink and thoroughly dry pipes and base of cabinet under sink. Run water on high (both hot and cold) to identify source of leak. For very small leaks, wrap a dry paper towel around the base of the vanity for a day or so and then check for water marks on the paper towels.