A short male-to-male 3/4″ NPT plastic union nipple with a built-in O-ring — the standard connector used between whole-house filter housings and inline components. Quantity discounts start at 2.

What it does

This union nipple connects two whole-house filter housings (or a housing to an inline component) that both take a 3/4″ NPT female port. The integrated O-ring seals against the mating face so a hand-tight fit doesn’t leak — no thread tape, no wrench torque, no over-tightening.

A standard, everyday plumbing part in multi-stage systems: you’ll typically use one nipple per housing-to-housing joint (so a 2-stage system uses 1, a 3-stage system uses 2, etc.). Buy an extra to keep in the parts drawer for future service.

Key benefits

• ✓Male × male 3/4″ NPT — the standard between-housing size in slim whole-house systems
• ✓Integrated O-ring — hand-tight, no thread tape, no leaks
• ✓Corrosion-proof plastic — won’t rust like brass or seize like steel
• ✓Fits all MyWaterClub 3/4″ whole-house housings, plus most standard-thread brands
• ✓Automatic quantity discounts starting at 2 units

Specifications

Compatibility

Often used with

Good to know before you buy

• Hand-tighten only, plus a quarter turn if needed to seat the O-ring. Do not use a wrench — over-torquing cracks the plastic and defeats the O-ring seal.
• Thread tape is usually not required when an O-ring is present, because too much tape can prevent the O-ring from seating properly. However, if additional sealing is needed, a few light layers of plumbing tape may be used.
• The O-ring is a wear part — if you disassemble and reassemble multiple times, inspect it and replace if nicked or flat.
• You typically need one nipple per housing-to-housing joint: 1 nipple for a 2-stage, 2 nipples for a 3-stage. Order an extra to keep on hand.
• Not rated for hot-water or high-pressure industrial lines — residential cold-water filtration only.
• Maximum pressure: 90 psi