Faucet & Plumbing O-Rings
EPDM and NBR seals for taps, showerheads, cartridges and hose connections. Potable water compliant.
Plumbing O-rings are the most commonly replaced seals in residential and commercial buildings. From the kitchen faucet to the showerhead, hose connection, and valve cartridge, these small seals prevent leaks that waste water, damage cabinets and floors, and drive up utility bills. This guide covers the sealing points in residential plumbing, the materials approved for potable water contact, and the common sizes needed for faucet repair. **Where O-Rings Seal in Faucets and Plumbing** **Faucet cartridge body.** Modern single-handle and dual-handle faucets use cartridge valves sealed by O-rings where the cartridge inserts into the faucet body. These seals must survive continuous water pressure (1–6 bar), temperature cycling from cold to hot, and the minerals and chlorine in municipal water. A leaking cartridge O-ring causes water to weep from the handle base or spout joint. **Faucet spout swivel joint.** Pull-out and pull-down kitchen faucets use an O-ring at the spout swivel joint to allow rotation while maintaining a watertight seal. This O-ring experiences both rotation and water pressure — a demanding combination that requires low-friction material and precise groove design. **Showerhead and handheld wand connections.** Showerheads and handheld wands thread onto shower arms with an O-ring or rubber washer seal. These seals must survive hot water (+40°C to +60°C), water hammer pressure spikes, and the constant opening/closing of the shower valve. EPDM is the standard material. **Hose connections and quick couplers.** Garden hose, washing machine hose, and dishwasher hose connections use O-rings or flat washers to seal against the faucet or valve outlet. These seals must survive outdoor UV (for garden hoses), hot water (for dishwasher hoses), and repeated connect/disconnect cycles. **Tap valve seats and gland seals.** Traditional compression taps (rising spindle taps) use O-rings or gland packings around the valve spindle to prevent water from escaping up the spindle when the tap is open. These seals must survive the full water pressure and the abrasive wear from turning the tap handle. **Potable Water Compliance** O-rings used in drinking water systems must comply with regional potable water standards. NSF-61 (North America) and WRAS (UK) are the most common certifications. [EPDM](/products/epdm/) is the standard material for potable water — it does not leach harmful substances and is approved for repeated water contact. [VMQ silicone](/products/vmq/) is also widely used in food-grade and medical-grade plumbing. [NBR](/products/nbr/) is acceptable for non-potable hot water but is less commonly certified for direct drinking water contact than EPDM.
Application Requirements
Recommended Materials
EPDM 70 Shore A
The standard for all potable water plumbing — faucets, showerheads, hose connections, and valve seals. NSF-61 and WRAS approved grades available.
Temp: -50°C to +150°C
Black or blue EPDM is the OEM standard for faucet O-rings. Resists chlorine and hot water. Do NOT use petroleum grease — use silicone grease or food-safe lubricant.
VMQ (Silicone) 70 Shore A
High-temperature plumbing near water heaters, steam valves, and food-service equipment. FDA and USP Class VI grades available.
Temp: -60°C to +230°C
More flexible than EPDM for small-diameter seals. FDA compliant for direct food contact. Not as durable as EPDM in abrasive mineral water.
NBR 70 Shore A
Non-potable hot water applications, utility sinks, and industrial washdown stations where NSF certification is not required.
Temp: -40°C to +120°C
Lower cost than EPDM but not recommended for direct drinking water contact without specific NSF approval. Hot water above +60°C accelerates NBR aging.
Design Tips
- 1.Use silicone grease or food-safe lubricant for all potable water O-rings. Petroleum grease contaminates drinking water and attacks EPDM.
- 2.Replace faucet cartridge O-rings when replacing the cartridge — the seal ages with the cartridge and will leak if reused.
- 3.Inspect showerhead O-rings annually — mineral deposits and chlorine harden the seal, causing leaks around the shower arm joint.
- 4.For hard water areas, inspect faucet O-rings every 6 months — mineral buildup accelerates seal degradation and causes leaks.
- 5.Do not overtighten plastic faucet fittings — excessive torque crushes the O-ring and cracks the plastic body.
- 6.Store spare plumbing O-rings away from ozone and UV — rubber seals harden during storage if exposed to air and light.
- 7.For pull-out kitchen faucets, replace the spout swivel O-ring at first sign of stiffness — a worn swivel seal causes the spout to leak during rotation.
- 8.Keep a faucet repair kit with common sizes (6×1.5, 8×1.5, 10×2, 12×2 mm) — most residential faucet leaks can be fixed with 2–3 standard sizes.
Common Sizes
| Size | Typical Use |
|---|---|
| Metric 6×1.5 mm | Small faucet cartridge seals, tap gland seals |
| Metric 8×1.5 mm | Standard faucet cartridge body seals (Moen, Delta, Kohler) |
| Metric 10×2 mm | Large faucet cartridge seals, shower valve body seals |
| Metric 12×2 mm | Showerhead connection seals, large valve body seals |
| Metric 14×2.5 mm | Hose connection seals, washing machine hose washers |
| Metric 16×2.5 mm | Garden hose quick-connect seals, large tap valve seats |
| Metric 19×2.5 mm | Large shower arm seals, commercial faucet connections |
Frequently Asked Questions
What O-ring material is best for faucet repair?
EPDM 70 Shore A is the standard for all potable water faucet repairs. It resists chlorine, hot water, and mineral deposits better than NBR and is NSF-61 approved for drinking water contact. VMQ silicone is an alternative for high-temperature applications near water heaters. Never use NBR for drinking water without specific NSF certification — it may leach substances not suitable for potable water.
Why does my faucet leak from the handle?
A leaking faucet handle is almost always caused by a worn or damaged cartridge O-ring. The O-ring seals the cartridge body where it inserts into the faucet. Over time, the seal takes compression set, hardens, or is damaged by mineral deposits. Fix: turn off the water supply, remove the faucet handle and cartridge, inspect the O-ring for cracks or flattening, replace with a new EPDM O-ring lubricated with silicone grease, and reinstall.
Can I use plumbing O-rings for drinking water?
Only if the material is certified for potable water contact. EPDM with NSF-61 certification is safe for drinking water. VMQ silicone with FDA 21 CFR §177.2600 certification is also safe. Standard NBR may not be certified for drinking water — verify the specific compound designation before using NBR in potable water systems. Look for NSF-61, WRAS, or KTW certification markings on the packaging.
What size O-ring fits a Moen faucet cartridge?
Moen single-handle cartridges (1225, 1222, 1255 series) typically use an 8×1.5 mm EPDM O-ring on the cartridge body. Moen two-handle cartridges use 6×1.5 mm or 8×1.5 mm depending on the series. Delta cartridges use 8×1.5 mm and 10×2 mm. Kohler cartridges range from 8×1.5 mm to 12×2 mm. Always measure the removed O-ring or check the manufacturer parts list — generic EPDM replacements are dimensionally identical.
How do I stop a showerhead from leaking at the connection?
Remove the showerhead from the shower arm, clean the threads and the O-ring groove, inspect the O-ring for cracks or compression set, replace with a new 12×2 mm or 14×2.5 mm EPDM O-ring, lubricate with silicone grease, and reinstall hand-tight plus 1/4 turn with a wrench. Do not overtighten — it crushes the O-ring and damages the threads.
Do you supply faucet O-ring repair kits?
Yes, we supply faucet and plumbing O-ring repair kits containing the most common metric sizes (6×1.5 to 19×2.5 mm) in NSF-61 EPDM for potable water repairs. Kits cover standard faucet cartridges (Moen, Delta, Kohler, Pfister), showerhead connections, hose fittings, and valve seals. Custom kits for specific faucet platforms are available on request. MOQ from 1 kit.
Need faucet and plumbing O-rings?
We supply EPDM and silicone O-rings and repair kits for faucets, showerheads, cartridges and hose connections. NSF-61 grades available. MOQ 1 piece.