Faucets have become more streamlined and a bit more complicated over the years, but faucet repair is no more difficult than it has ever been. In the days of yore, a plumber only needed to know how to fix a compression faucet, but modern faucets can have one of three other valve mechanisms that were developed around the middle of the 20th century. The repair procedure for each of these mechanisms is different, but none is difficult, and any DIY homeowner with the proper tools and a modicum of plumbing expertise can handle it.
What Exactly Needs Fixing?
When you have a leaky sink faucet that either drips from the spout or spews water from the handle, you can usually trace the problem to the valve. As plumber Mike Diamond points out, the three available types of faucets — not including compression faucets, which aren't that common anymore — feature either a cartridge, ceramic disk or ball valve.
If the valve itself isn't at fault, the problem is usually due to the rubber gaskets and O-rings that are part of it. All these parts, including the valve, are replaceable. For most faucets, they are easy to find.
A malfunctioning faucet can also cause poor water flow. The most common reason this happens is because hard-water deposits are blocking the aerator (on the end of the faucet spout) or the water-supply ports inside the valve or the valve housing. It's easy to clean the aerator, and you can often clean the valve, but sometimes, you need to replace part or all of the valve.
A leaking faucet can also spray water into the sink cabinet, and this is a somewhat more serious condition because of the damage it can do, but it isn't due to the valve. The problem is usually a loose connection on the faucet hoses or on the hoses that connect the spout to the handles or the sprayer. Although it entails working in a cramped space with little light, an under-cabinet leak is usually easy to locate and fix.
Faucet-Repair Tools and Supplies
Two tools you need for any faucet repair are a Phillips screwdriver and a pair of locking pliers, which do the job of tightening nuts and fittings better than a wrench. Depending on the type of faucet, you may also need a set of hex wrenches (the most common size needed is 1/8 inch) for removing the setscrew for the faucet handle as well as a flat-head screwdriver to pry off the cap hiding it. A pair of needle-nose pliers comes in handy for retrieving gaskets from inside the valve housing.
The supplies you may require depend on the repair, but it's always a good idea to bring a roll of plumbing tape to the job. It comes in handy when you have to seal leaky fittings on the supply hoses. If you're having water-flow problems, you should also have a bottle of plain, white distilled vinegar on hand for dissolving scale. Finally, don't forget spare O-rings, gaskets and other rubber parts, which come in model-specific repair kits that also include the hardware you need.
How to Repair a Leaky or Clogged Faucet
Step 1: Identify Your Faucet
It's easy to overlook this crucial step until you get to the hardware store and find out that faucets are like cars when it comes to buying parts and repair kits: You need to know the make and model. Every faucet maker has its own distinctive logo, which you can usually find on the faucet handle, and having done that, you can look up the model on its website along with model-specific repair instructions and a list of recommended replacement parts, which you can order online from the manufacturer or a third-party supplier.
Some types of faucets are more likely to come from a particular manufacturer than others. For instance, if you have a ball-valve kitchen or bathroom faucet, it's probably a Delta, and if you have a Euro-style one with squared-off edges, it's more likely to be a Grohe or Kohler than a Moen, Delta, Pfister or American Standard.
Step 2: Clean the Aerator
A clogged aerator is the most common cause of reduced water flow. Unscrew the aerator and backflush it under the faucet or soak it overnight in a bowl of vinegar to descale it if necessary. If the aerator is recessed and you can't grip it with pliers, you may need to purchase an inexpensive aerator key from a plumbing-supply outlet.
The aerator for pull-down and pull-out faucets is usually located behind the spray head. Unscrew the spray head and pull out the aerator from the head or the hose for cleaning using needle-nose pliers
Step 3: Turn Off the Water
The shut-off valves are usually located under the sink, and you turn them off by rotating them clockwise. If you can't find shut-off valves, which happens, you may have to turn off the main water valve for the house. If you need to make a repair to the hot side of a two-handle faucet, you can shut off the water-supply outlet at the water heater instead.
You don't have to turn off the water for some repairs, such as cleaning the aerator or replacing the handle.
Step 4: Disassemble the Faucet
Begin disassembly by removing the handle. To do this, you have to locate the setscrew. It may be on the base of the handle, under the lever or hidden behind a cap that you have to pry off with a flat-head screwdriver. You can remove most setscrews with a 1/8-inch hex wrench. If you don't see a setscrew and the handle has a large tapered base, try unscrewing the base.
Once you've pulled off the handle, the rest of the disassembly depends on the faucet, but it usually involves unscrewing a retaining nut with locking pliers. If you're servicing a ball-valve bathroom or kitchen sink faucet, you have to unscrew a dome-shaped collar to access the valve. Remove it slowly to avoid losing any of the small valve parts down the drain. In fact, it's a good idea to cover the drain for any faucet repair.
Step 5: Service the Valve
Once you've exposed the valve, you should be able to remove it by gripping the valve stem with pliers and pulling. Ball valves come out very easily (no need for pliers), but cartridge, disk and compression valves can get stuck by scale. If you can't get the valve out by wiggling, pulling and dousing with vinegar, you may need to buy a valve puller, which is a device that works like a corkscrew.
Once you have the cartridge, disk, compression valve or ball valve in your hand, inspect it for nicks, cracks and other defects that would cause it to leak and replace it if you find any. Pull out all the rubber parts and springs from the valve housing and replace them using new parts from a repair kit. If the faucet was clogged, soak the valve overnight in vinegar and scrape scale from the valve seat using a screwdriver.
Step 6: Reassemble the Faucet
Reverse the disassembly procedure to reassemble the faucet. Check the valve for marks indicating the proper orientation and make sure those marks line up with the ones on the valve housing. Tighten everything securely with locking pliers but don't overdo it. You don't want to crack anything, and you want to make sure you're able to disassemble the faucet again in the future.
Step 7: Stop Under-Cabinet Leaks
Clear off the cabinet shelves and look for spraying water, which you'll see only if you don't turn off the water. If a leak is coming from a hose connection and the connection has compression fittings, tighten the connection with locking pliers.
If the connection has quick-disconnect fittings, they will be plastic, and you'll see a tab or button you can press. The main reason these leak is because they weren't connected properly in the first place. To rectify that, turn off the water and drain the faucet. Then, grasp the fitting with both hands, push the tab or button, pull it apart and push it back together until it clicks.
Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker.com.