How to Fix a Leaking Bathtub Faucet (and When to Call a Plumber)

A dripping bathtub faucet is more than just an annoying sound at night. A faucet that drips once per second wastes over 3,000 gallons of water per year, which adds up on your water bill and puts unnecessary strain on your plumbing system. In New York City, where water and sewer charges are among the highest in the country, a leaking faucet is literally money going down the drain.

In this guide, we will cover the most common causes of a leaking bathtub faucet, basic repair steps you can try yourself, and when it is time to call a Licensed Master Plumber to handle the job properly.

Common Causes of a Leaking Bathtub Faucet

Understanding why your faucet is leaking helps you determine whether it is a quick fix or a more serious plumbing issue.

Worn Cartridge or Stem

Most modern bathtub faucets use a cartridge that controls the flow of water. Over time, the seals inside the cartridge wear out, allowing water to seep through even when the handle is fully closed. In older NYC buildings, you may have a compression-style faucet with a rubber washer on a stem. These washers harden and crack with age, losing their ability to create a watertight seal.

Damaged O-Rings

O-rings are small rubber rings that create seals at various connection points inside the faucet. When they deteriorate, water leaks around the handle or from the spout. O-ring failure is one of the most common and least expensive faucet problems to fix.

Corroded Valve Seat

The valve seat is the connection point between the faucet and the spout. Over time, mineral deposits from NYC's hard water can corrode the valve seat, preventing the washer or cartridge from seating properly. A corroded valve seat will cause a persistent drip from the spout even after you replace the washer or cartridge.

Worn or Broken Diverter

If your bathtub has a shower, the diverter valve switches water flow between the tub spout and the showerhead. A worn diverter can cause water to leak from the tub spout when the shower is running, or cause a constant drip from either outlet.

High Water Pressure

Excessively high water pressure can prevent faucets from closing completely, causing a drip. If multiple faucets in your home are dripping, high water pressure may be the underlying cause rather than a problem with any individual faucet.

DIY Steps for Basic Faucet Repairs

If you are comfortable with basic tools, you can attempt some of these repairs yourself. Here is what to do:

Step 1: Turn Off the Water

Before touching anything, shut off the water supply. Look for shutoff valves behind an access panel near the tub. If there are no dedicated shutoff valves for the tub, which is common in older NYC apartments, you may need to shut off the water to the entire unit or building.

Step 2: Remove the Handle

Pop off the decorative cap on the handle, remove the screw underneath, and pull the handle off. Some handles require a handle puller if they are stuck due to mineral buildup.

Step 3: Inspect the Cartridge or Stem

Once the handle is removed, you can access the cartridge or stem assembly. Remove it and inspect for visible damage, wear, or mineral deposits. Bring the old part to a plumbing supply store to find an exact replacement.

Step 4: Replace Worn Parts

Install the new cartridge, washer, or O-rings. Apply plumber's grease to rubber components before installation to ensure a smooth seal and extend their lifespan.

Step 5: Reassemble and Test

Put everything back together in reverse order, turn the water supply back on slowly, and test the faucet. If the drip stops, you have solved the problem.

When the Problem Is Deeper

Sometimes a dripping bathtub faucet is a symptom of a more significant plumbing issue that DIY repairs cannot solve:

• Corroded valve body. If the valve body behind the wall is corroded, replacing the cartridge will not stop the leak. The entire valve assembly needs to be replaced, which requires cutting into the wall.
• Galvanized pipe corrosion. Many pre-war NYC buildings have galvanized steel supply pipes that corrode from the inside. Mineral deposits can break off and damage faucet components. If your faucets keep failing despite new parts, deteriorating pipes may be the root cause.
• Incorrect parts. NYC buildings have plumbing from every decade of the past century. Finding the right replacement parts for antique or discontinued faucets can be difficult. A Licensed Master Plumber has access to specialty suppliers and the knowledge to identify obscure faucet models.
• Behind-the-wall leaks. If water is seeping into the wall cavity behind the faucet, the damage may be invisible from the bathroom side. You might notice water stains on the ceiling below, peeling paint, or a musty smell. These leaks require professional diagnosis with leak detection equipment.

NYC-Specific Considerations

Working on plumbing in New York City comes with unique challenges:

• Old buildings, old plumbing. Many NYC apartments have plumbing that is 50 to 100 years old. Parts may be obsolete, pipes may be fragile, and the plumbing layout may not follow modern conventions.
• Permit requirements. While replacing a faucet cartridge does not require a permit, any work that involves modifying supply piping behind the wall requires a Licensed Master Plumber and may require a DOB permit.
• Co-op and condo rules. Many buildings require that plumbing work be performed by a licensed professional. Check with your building management before attempting DIY repairs.
• Water damage liability. In a multi-unit building, a plumbing mishap in your apartment can cause water damage to the unit below. If you are not confident in the repair, hiring a professional is the safer and often less expensive choice in the long run.

When to Call a Licensed Master Plumber

Call a professional when:

• The faucet continues to drip after you have replaced the cartridge and washers.
• You cannot find the right replacement parts.
• There are signs of water damage behind the wall or on the ceiling below.
• The valve body or piping behind the wall needs to be replaced.
• You want to upgrade to a new shower and bath fixture.
• Your building requires Licensed Master Plumber work for any plumbing repairs.
• Multiple faucets are leaking, suggesting a water pressure issue or deteriorating supply pipes.

Karl's Plumbing, Heating & Cooling has been handling residential plumbing repairs across New York City for four generations. Our Licensed Master Plumbers (LMP #921 and LMP #2060) can diagnose and fix any faucet problem, from a simple cartridge replacement to a complete valve rebuild behind the wall.

Call us at (800) 721-3200 or (718) 263-8600. We are available 24/7 for emergency plumbing throughout Manhattan, Brooklyn, Queens, the Bronx, Staten Island, Long Island, and Westchester.