Faucet O-Ring and Washer Replacement: Why Faucets Drip and How to Fix Them

Most faucet drips and handle leaks come down to two small rubber parts: an O-ring or a washer. O-rings seal the rotating or reciprocating stem against the faucet body — when they wear, water escapes around the handle. Washers seat against a brass valve seat to stop flow — when they compress flat or crack, water drips through the spout. Both repairs cost $3–$15 in parts and take under 45 minutes. Here’s how to identify which you need and how to replace it.

How to Replace an O-Ring on a Faucet

O-rings on a faucet stem seal the area where the stem passes through the faucet body. When they wear, water seeps past them and appears around the handle or at the base of the spout.

For a compression faucet (two separate handles that turn multiple times):
1. Shut off the supply valve under the sink — hot and cold
2. Remove the handle: pry off the decorative cap, remove the screw underneath, pull the handle off
3. Use an adjustable wrench to unscrew the packing nut (the large hex nut holding the stem in place)
4. Pull the stem straight out — you’ll see one or more O-rings on the stem body
5. Slide the old O-rings off; bring them to a hardware store to match the size exactly
6. Coat the new O-rings lightly in plumber’s grease before installing
7. Slide the new O-rings onto the stem in the same positions
8. Reassemble in reverse; turn on supply and test

For a cartridge faucet (single or double handle, quarter-turn):
O-rings are usually on the cartridge body itself. Remove the cartridge and inspect — if the O-rings on the cartridge body are cut, cracked, or flattened, replace them or replace the entire cartridge. See our faucet cartridge replacement guide for the cartridge removal process.

Faucet Still Dripping After I Replaced the Washer — Why?

The most common reason: the valve seat is damaged. The valve seat is the brass surface inside the faucet body that the washer presses against to stop water flow. If the seat is pitted, corroded, or rough, a new washer can’t seal against it completely — and the drip continues even with a perfect new washer.

Other reasons a drip persists after washer replacement:
– Wrong washer size: A washer that’s too small won’t make full contact with the seat; too large and it deforms rather than seating flat
– Washer installed incorrectly: Beveled washers have a correct orientation — flat side against the seat
– Packing nut too loose: If the packing nut isn’t snug, water bypasses the washer seal
– Seat is worn past what a washer can compensate for: A seat wrench or seat replacement is needed

To check the seat: after removing the stem, shine a flashlight into the faucet body and look at the brass seat. A smooth, even ring means it’s in good condition. Pitting, rough texture, or visible corrosion means it needs resurfacing with a seat wrench tool or replacement.

What Causes a Faucet O-Ring to Wear Out?

O-rings are made of rubber (or EPDM rubber in newer faucets) and wear through:

• Physical friction: Every time you operate the handle, the O-ring slides slightly against the faucet body. Over thousands of cycles, this abrasion thins the rubber.
• Heat cycling: Hot water causes rubber to expand and contract. Over years, this cycling hardens and cracks the O-ring.
• Chlorine degradation: Chlorinated water supplies gradually break down rubber compounds. Seattle and Tacoma both chlorinate their water — this is unavoidable but is the main chemical aging factor.
• Overtightening: Homeowners who tighten a leaking handle to stop a drip compress the O-ring beyond its design range, permanently deforming it.

Average lifespan: 7–15 years under normal use. Faucets used frequently (kitchen sinks) see faster O-ring wear than lightly used fixtures.

How to Find the Right Size O-Ring for a Faucet

O-rings are measured by their inner diameter (ID) and cross-section diameter (CS). Standard plumbing O-rings use sizes designated by a number system (e.g., #14, #15, #16) or by fractional inch measurements.

The most reliable method: take the old O-ring to a hardware store and match it physically. Lay the old O-ring on a flat surface next to candidates in the display until the diameter and cross-section match. An O-ring that’s even 1/32 inch off in cross-section may not seal correctly.

If the old O-ring is destroyed and you can’t measure it: measure the groove it sat in. The O-ring cross-section should be slightly larger than the groove depth so it compresses into a seal.

Most hardware stores carry assorted O-ring kits for $5–$10 that include the most common plumbing sizes — a kit is often more cost-effective than buying individual O-rings if you’re uncertain of the size.

TIP: Always coat a new O-ring with plumber’s grease (silicone grease) before installation. This reduces installation friction that can cut the O-ring as it’s seated, and extends the O-ring’s service life significantly. Do not use petroleum-based lubricants — they degrade rubber.

Faucet O-Ring Replacement Cost — DIY vs. Plumber

DIY cost:
– Individual O-ring: $0.50–$2
– O-ring assortment kit: $5–$10
– Plumber’s grease: $4–$6
– Total: $3–$15

Plumber cost (Seattle 2026):
– Service call: $95–$175 for the first hour
– O-ring replacement is typically completed within the service call time
– Total with service call: $95–$200

Because the parts cost so little and the repair is accessible to a confident homeowner, this is one of the strongest cases for DIY plumbing repair. The only reason to call a plumber for an O-ring: if the valve seat is also damaged (adding a seat resurfacing job), or if the faucet is an unusual model where disassembly requires specialized knowledge.

How to Stop a Faucet Leaking at the Handle

A leak specifically at or around the handle — not at the spout tip — means water is escaping where the stem meets the faucet body. The fix depends on faucet type:

Compression faucet:
Replace the packing washer (a flat rubber disc around the stem) and the O-rings on the stem body. These are the primary seals at the handle-to-body junction.

Cartridge faucet:
The O-rings on the cartridge body are worn. Remove the cartridge and inspect the O-rings — replace them individually if they’re cut or cracked, or replace the entire cartridge if O-rings and cartridge are both worn.

Ball faucet:
O-rings on the ball housing are worn. Buy a complete ball faucet repair kit — it includes the O-rings, ball, springs, and seats. Replace everything in the kit rather than just the O-rings.

In all cases: shut off supply valves, disassemble to the relevant part, swap the O-ring(s), coat with plumber’s grease, reassemble.

Compression Faucet Washer vs. Cartridge — Which Do I Have?

Compression faucet:
– Has two separate handles — one hot, one cold
– Handles require multiple full turns from closed to fully open
– Each handle screws in to stop flow (you feel increasing resistance as you close them)
– Common in homes built before 1980 and in some utility sinks today
– The drip fix is washer replacement

Cartridge faucet:
– May have one or two handles
– Handles rotate approximately 90–180° from off to fully on (not multiple turns)
– Each handle clicks or stops at the open position
– The most common type in homes built or remodeled after 1980
– The drip fix is cartridge replacement (which includes internal O-rings)

Ball faucet:
– Single handle that rotates in multiple directions (side for temperature, up/down for flow)
– Common in older Delta kitchen faucets
– The drip fix is a ball, seat, and spring replacement — buy a kit

If you’re still not sure: unscrew the handle and look at what’s underneath. A threaded stem with a rubber washer at the bottom = compression. A cylinder that pulls straight out = cartridge. A rotating ball = ball type.

Faucet Washer Keeps Wearing Out — Why?

If you’re replacing faucet washers frequently — every 6–18 months — something is accelerating wear beyond normal:

1. Damaged valve seat: A pitted or rough seat destroys washers quickly. Every operation grinds the washer against the irregular surface. Fix the seat and washer life returns to normal.
2. Wrong washer material: Not all rubber is equal. Buna-N (nitrile) washers handle chlorinated water better than natural rubber. Use nitrile washers in Seattle and Tacoma water systems.
3. High water pressure: Pressure above 80 PSI accelerates mechanical wear on washers and O-rings. Check system pressure — if it’s high, PRV adjustment will reduce wear rates house-wide.
4. Overtightening the handle: Closing a faucet with excessive force compresses the washer past its designed limit. Tighten until snug, not as tight as possible.

How Long Does a Faucet O-Ring Last?

Under normal conditions with properly sized installation and plumber’s grease applied at installation: 7–15 years.

Factors that shorten lifespan:
– High water pressure (above 70 PSI)
– Chlorinated water supply (chemical degradation)
– Frequent use (kitchen faucets wear faster than guest bathroom faucets)
– Overtightening handles
– Original installation without grease

Factors that extend lifespan:
– Nitrile or EPDM rubber (versus natural rubber)
– Moderate water pressure (50–65 PSI)
– Plumber’s grease applied at installation and re-applied when serviced
– Soft water (lower mineral abrasion)

In most Seattle homes: plan for O-ring replacement roughly every 10–12 years per fixture. Kitchen faucets may need it after 7–8 years due to heavier use.

Faucet Leaking from Stem — What Part Do I Replace?

A leak from the stem area — visible water seeping around the packing nut or where the stem exits the faucet body — almost always means the packing material or O-rings around the stem have failed.

On compression faucets: Replace the packing washer (a flat rubber or graphite disc immediately under the packing nut) and the O-rings on the stem body.

On cartridge faucets: The stem is part of the cartridge. Replace the cartridge — the O-rings are integral to the cartridge body and aren’t separately serviceable in most designs.

Packing nut leak (if the nut itself is weeping): Try snugging the packing nut slightly — it may just need a quarter-turn tightening. If tightening doesn’t stop the seep, the packing material inside is worn and needs replacement.

For a detailed step-by-step on cartridge-type stems, see our faucet cartridge replacement guide.

FAQ

Q: What’s the difference between an O-ring and a washer in a faucet?
A: An O-ring is a round rubber loop that seals a rotating or sliding shaft — it’s what keeps water from leaking around the stem or spout body. A washer is a flat rubber disc that seals against a valve seat to stop flow through the faucet. O-ring failures cause handle or base leaks; washer failures cause spout drips.

Q: How do I know if I need an O-ring or washer replacement?
A: Where does the water appear? At the handle or base = O-ring. At the spout tip when the faucet is off = washer (or cartridge on modern faucets). The location of the leak tells you the part.

Q: Can I use any rubber O-ring for a faucet repair?
A: No — size matters significantly. Too small and it won’t seal; too large and it won’t seat correctly. Always match the exact size of the old O-ring. Use nitrile or EPDM rubber for chlorinated water systems. Do not substitute petroleum-based O-rings (they degrade in water).

Q: How much does it cost to fix a faucet O-ring leak in Seattle?
A: DIY: $3–$15 for O-rings and grease. Plumber: $95–$200 including service call (2026 Seattle rates). For a current estimate based on your faucet type, use the cost estimator.

Q: Should I replace just the O-ring or the whole cartridge?
A: If the cartridge is under 10 years old and otherwise in good condition, just the O-ring is fine. If the cartridge is over 10 years old or the drip comes from the spout (not just the handle), replace the whole cartridge — the sealing surfaces inside it may be worn even if the O-rings look okay.