Dripping Faucet: Cartridge, O-Ring & Seat Washer Diagnosis by Faucet Type

Common Symptoms

• Drip from the spout when faucet handles are off
• Drip rate increases when handles are tightened further
• Water dripping from the base of the spout (O-ring leak)
• Handles difficult to turn or feel gritty
• Squeaking sound when turning handles

Most Likely Causes

1. 1

   Worn Cartridge (Cartridge Faucets — Most Common Single-Handle)

   Single-handle kitchen and bathroom faucets use a cartridge — a sealed plastic or ceramic cylinder that controls hot/cold mixing and flow. When the cartridge wears out, water seeps past the seals and drips from the spout. Pull the cartridge and replace with an exact-match replacement (model-specific).

2. 2

   Worn Seat Washer (Compression Faucets — Older Two-Handle)

   Two-handle faucets with separate hot and cold knobs (common in homes built before 1980) use a compression mechanism. A rubber washer compresses against a brass seat to stop flow. When the washer wears out, water bypasses it. The fix is removing the handle, unscrewing the packing nut, and replacing the washer at the bottom of the stem.

3. 3

   Worn Ball and Springs (Ball Faucets — Single-Handle Kitchen)

   Ball faucets (most common in kitchens — the single handle moves in an arc) use a rotating ball with springs and rubber seats. Over time the springs weaken and the seats wear, allowing water to drip. Replace the seat and spring kit ($10–$20) rather than individual pieces.

4. 4

   Damaged O-Ring (Base Drip)

   If water is dripping from the base of the spout (not the tip), the O-rings on the valve body are the cause. O-rings are cheap rubber rings that seal the spout to the faucet body. Replace them with the correct diameter O-ring from the hardware store.

5. 5

   Ceramic Disc Crack or Contamination

   Premium faucets use two ceramic discs that rotate to control flow. The discs are very durable but can crack from thermal shock or chip from mineral deposits. Clean the discs with white vinegar — if still leaking, replace the disc cylinder.

Quick DIY Checks

1. 1Identify your faucet type: Single handle that moves side-to-side = ball faucet. Single handle that moves up/down and side-to-side = cartridge faucet. Two separate hot/cold handles that you screw in/out = compression faucet. Premium single-handle bathroom = likely ceramic disc.
2. 2Shut off water supply: turn the shutoff valves under the sink clockwise until they stop. Turn on the faucet to relieve pressure in the line.
3. 3Remove the handle: pry off the decorative cap on top of the handle to reveal a screw. Remove the screw (usually Phillips or hex/Allen) and pull the handle straight up.

1. 4For cartridge faucets: use pliers to pull the cartridge straight up. Take the old cartridge to the hardware store for an exact match — Moen, Delta, Kohler all have model-specific cartridges. Install new cartridge in the same orientation.
2. 5For compression faucets: unscrew the packing nut with pliers, pull out the stem, and note the washer size at the bottom held by a brass screw. Replace the washer and reinstall.
3. 6For ball faucets: purchase a ball faucet repair kit for your brand (Delta, Moen, Price Pfister). Kits include new ball, springs, seats, and O-rings. Follow the kit instructions — replace all components at once for lasting results.

Repair vs Replace

Recommended Tools & Parts

• Faucet Cartridge (Brand-Specific)

  Replacement cartridge for single-handle faucets. Moen, Delta, Kohler — bring the old cartridge or your faucet model number for an exact match.

  $10–$30

  Buy on Amazon →

• Faucet Seat and Spring Kit

  Rubber seats and springs for ball-type faucets. Brand-specific — buy the kit for your faucet brand.

  $8–$20

  Buy on Amazon →

• Faucet O-Ring Assortment

  Assorted rubber O-rings for faucet base drips and packing nut seals. Bring the old O-ring to match diameter.

  $5–$12

  Buy on Amazon →

Links are Amazon affiliate links (tag: fixitfastai-20). Prices are estimates.

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