Faucets have internal parts that eventually wear out. The first to go are the washers and o-rings, then the seats, and then possibly the stem. As these parts wear you will start to get leaking from your faucet. The leaks could come from the spout and drip into the sink, or you could get leaking from the handle(s) and have water running on to your counter or under the counter. Just before we get into repairing your faucet let’s consider a couple of things.
For you water conservationalists its out there did you know that 1 drop of water per second equals about 2,500 gallons of water per year? And most people that I have repaired faucets for wait until there faucet is leaking about 6-10 drips per second. That is about 12,500 to 25,000 gallons of water per year. That’s $80 to $140 per year. Plus most of your leaks will start on the hot side way before the cold, since the hot water will deteriorate the rubber in the valves much quicker. So with the way energy costs are today you can add 30% to 60% to those costs.
If your bathroom faucet is 10 years old or older you may wish to change the faucet out with a new one. I definitely recommend doing this. The reason I believe you should do this is that the labor for repairing the faucet and the labor for replacing the faucet are fairly close to the same. And the parts for repairing the faucet will be around $35.00. A new faucet will cost you around $75.00. So for only an extra $40.00 you will have a nice new faucet to brighten up your bathroom.
With your kitchen faucet the price difference can be much more significant. In either case you will need to make a decision that fits your situation the best.
Now with the bath tub or shower faucets, since the valve is behind the wall, then I recommend repairing the leak. The best time to replace a bath tub or shower faucet is during renovations. It is possible for you to replace sooner if you have enough access to the faucet from the back. So you could replace with a similar faucet or there is a flange made by delta that will cover holes left from a two or three handle faucet when you install a single lever faucet.
This is an absolutely huge area. There is literally thousands of different faucets and models of faucets over the last 30 years.
A short list of the more common styles are:
Two handle bathroom, kitchen, bathtub or shower faucets with seats and washers
Two handle washerless bathroom, kitchen, bath tub or shower faucets
Three handle bath/shower faucets with seats and washers
(these will have a hot and cold tap as well as a control for the bath/shower)
Single lever bath/shower faucets with cartridge
Single lever kitchen faucets with pull-out head and cartridge
Single lever kitchen and bathroom faucets with rubber seats and ball control
The reason I say short list is because each of the above can have many different variations. There are dozens of different seats, washers, and cartridges. Because there is so many different styles and variations the time to make the repair can become longer because quite often you will need to go to a specialty shop to match the parts with the parts you removed. So you can understand that if you are paying a plumber $75.00 per hour (that is the going rate here) the replacement of the faucet may be cheaper than the repair of the faucet.
Now on to the faucet repair job
Each type of faucet will have a similar repair procedure. I suggest putting the parts in order on the counter beside you as you pull them out so that you know exactly how to put them back again.
1. Turn off the water.
2. Pry off the handle screw cover.
3. Take the screw out of the handle
4. Remove handle (you may need handle pullers to do this)
5. Remove escusion if there is one (usually on two handle bath tubs and showers)
6. Loosen off the holding nut (in single lever bathtub showers there is a holding ring)
7. Remove the stem (cartridge in single lever bath/showers)
8. Check the brass seats for cuts (use your baby fingernail or flashlight)
(remove rubber seats if you have a washerless faucets)
9. Replace brass seats if necessary (the seats might be chrome as well)
10. Replace the washer (replace the cartridge in single levers)
11. If need be replace the stem.
12. Put back together
13. Check for leaks.
Congratulations! You just saved yourself $100-$200 repairing your own faucet