Faucet leaks through valve

there might be a allan screw holding it down usually located at the back of the faucet if not there is a chance that there is a screw on escutcheon just above the base of the spout this should screw off with a strap wrench.

Unscrew top button.
Using a phillips screw driver remove handle retaining screw and work off handle.
If it leaks under the handle you need to unscrew the top cap, use a strap wrench to hold the body and tighten the brass retainer ring with an adjustable wrench. Or remove the ring to replace the cartridge.

These faucets can leak in three different places:

1. Internally at the valve seat
   You'll see water dripping from the spout. This means the rubber washer is worn or damaged. To replace the washer, remove the decorative cap from the handle. Remove the retaining screw and pull off the handle. Remove the decorative cover, called an escutcheon, if there is one. Unscrew the packing nut counterclockwise. Unscrew the valve stem and remove it. Remove the screw that holds the rubber washer in place. Because these washers come in many shapes and sizes, you'll want to take the old one to the hardware store and buy an exact replacement. Be sure to buy two washers so you'll have one for the other valve. Replace the washer and reassemble the faucet.
   
2. Around the handle
   If you see water coming from below the handle, the packing nut is leaking. Older faucets have a string-like graphite packing material wrapped around the stem. Newer faucets use an O-ring. First try tightening the packing nut clockwise... about one-half turn. If this doesn't stop the leak, remove the packing nut and replace the packing or O-ring; then reassemble the faucet. If the valve is using the graphite packing material, it might be a clue that you should shop for a new faucet.
   
   
3. Between a pivoting spout and the body
   The spout might be held in place with a packing nut, similar to the faucet stem, or it might have a nut at the top of the spout. In either case, remove the spout and replace the packing material or the O-ring seal. Then reassemble the faucet.

Single lever faucets also are known as "washerless" faucets. They are easier to repair than compression faucets after you determine what type of faucet you have. There are three types of washerless faucets: ball, ceramic disk and cartridge.
Leaks are evident in two places... dripping from the spout and seeping from around the spout where it joins the body of the faucet.
Leaks from the spout indicate that the ball, disk or cartridge is leaking. To repair, turn off the water to the faucet, then remove the handle. The handles on ball-type faucets are held in place with a setscrew that requires an Allen wrench to loosen. Ceramic disk and cartridge-type handles usually are held in place by a screw hidden beneath a cap.
On ball and ceramic disk-type faucets, remove the ball or disk and replace the seals. You can buy replacement kits for these faucets at the hardware store or home center.
On cartridge-type faucets, remove the spout and pull out the retainer clip that holds the cartridge in place. To remove the cartridge, pull on the cartridge stem with a twisting motion. If it resists, install the handle so you can a better grip on the cartridge to pull it out. Take the cartridge to the hardware store or home center and purchase an exact replacement kit.
Reassemble the faucet according to directions.
Leaks at the spout-to-body joint indicate an O-ring failure. Disassemble the faucet as described above. Remove the spout sleeve and replace the O-rings. It's a good idea to replace these seals if you have the faucet disassembled for repair of the ball, disk or cartridge.

1 Close the hot and cold water valves in the cabinet beneath the sink to shut the water supply off to the bath faucet.

2 Remove the bath faucet's handle to access the valve cartridge. The faucet handle is removed by first detaching the handle's insert cap using the tip of a screwdriver or utility knife to expose the handle screw. Remove the handle screw with a Phillips screwdriver, then pull the handle off the valve cartridge stem.

3 Loosen and remove the cartridge valve nut with an adjustable wrench. Some faucet models retain the valve cartridge with a snap ring and are removed with snap ring pliers.

4 Pull the old valve cartridge out of the bath faucet base, using pliers.

5 Insert the new replacement valve cartridge into the faucet housing and replace the nut or snap ring removed in Step 3, using an adjustable wrench or snap ring pliers.

6 Reinstall the faucet's handle onto the valve cartridge post, then secure the handle's screw, using a screwdriver.

7 Replace the insert cap into the handle to cover the handle's screw hole.

8 Turn on the hot and cold water valves beneath the sink to restore the water supply.

Hi,

I will try to help you.

The faucets with one-handle control have a valve cartridge inside the stem which needs to be replaced when a leak develops. Each manufacturer makes its own type of valve cartridge, so you must get exactly the valve that your faucet needs. The best way to do this is to remove the valve and take it to the hardware store when you don't know your model number. Each manufacturer also makes more than one valve so you must either know the model or take the valve in.

I can give you instructions on how to disassemble:

First , turn of both hot and cold water off beneath the sink.

Pop the cap off the top of the stem with a screw driver or knife, etc. You'll see a screw which must be removed to lift the handle off. Once the handle is off, you'll need to use a adjustable wrench or slip-joint pliers to remove the retaining nut. You will see one or more o-rings which must also be replaced. Be sure to lubricate them when reassembling.
Once the retaining nut and o-rings are off, you can use a pair of pliers to lift out the old cartridge. Please be sure to take note of the direction of the notch at the top of the stem. Mark it if you have to. When reassembling, be sure the notch is lined up in the same direction it was when uninstalling.

Reinassemble in reverse order.

Hope this helps, if it does, please place a vote or comment for me. Thanks,

Handie Andie

Turn the water off at the faucet, remove the handle and the retaining nut that is apart of the trim. You will see where you can use a wrench to remove it. The ball assembly will come right out and you can replace the washers right below it. Put it back together and if needed, tighten the tension ring that is on the retaining nut (usually grey or white in color) so it won't leak water around the ball stem. Good luck.

Remove the handle with an allen wrench. There is a grey retaining ring where the stem is coming out of the housing. Tighten the retaining ring. This will solve your problem. I'm shocked that it's not leaking as well. You might need new washers as well but try tightening the retaining ring first.

After some additional experimenting, contrary to information I was previously able to gather, I discovered that the white plastic retainer doesn't (in this type of Moen faucet) actually screw off but rather is held in place by a spring clip inserted from the rear of the retainer (toward the wall side of the basing). Simply sticking a small screwdriver in the opening (approx. 45 degrees downward) and tipping the screwdriver toward the front of the faucet, snaps the spring clip out through the opening.
The plastic retainer than lifts off. Note: the flat sides on the retainer suggest that a wrench will be needed but such is not the case.

I have the same problem. The part that is needed is found with a simple Google search for "Delta Waterfall RP22934 O-Rings"

Simply Slide the collar up at the base of the spout where it swivels.

Gently open the now exposed split plastic retainer so that the tabs near the bottom are pulled from their holes.

Lift the spout off the base to expose the o-rings.

Replace with the new o-rings and apply o-ring grease.

Re-assemble and enjoy a dry sink area.