Whole House Water Filter Housing: Types, Care & When to Replace

The filter housing is the part of your whole house water filter that most people never think about — until it starts leaking. Here’s a practical guide to the different housing types, how to care for them, and when to replace them.

Browse our whole house filter range including Big Blue single, twin, and triple stage systems, or see our Whole House Water Filters Guide.

What Is a Filter Housing?

The filter housing (also called the filter bowl or sump) is the sealed vessel that holds the filter cartridge in place and directs water through it. It connects to your plumbing via inlet and outlet ports and must maintain a watertight seal under mains water pressure. The housing itself doesn’t filter anything — that’s the cartridge’s job — but a failing housing means leaks, pressure loss, and contaminated water bypassing the filter entirely.

Housing Types

Blue or White Polypropylene Housings (Most Common)

The standard choice for Australian whole house installations. Chemically resistant, durable, and suitable for residential, commercial, and industrial use. Available in 5", 10", and 20" lengths in Slim, Standard, and Giant (Big Blue) sizes. Blue housings block UV light — important for outdoor or semi-exposed installations to prevent algae growth inside the housing.

Clear Housings

Allow visual inspection of the cartridge without removing the housing — useful for monitoring cartridge condition and water colour. Made from Styrene Acrylonitrile (SAN) or Polycarbonate. Not suitable for UV-exposed locations — use blue housings outdoors.

High-Temperature Housings (Red/Black)

Glass-reinforced nylon construction for commercial and industrial applications involving hot water or elevated temperatures.

Stainless Steel Housings

For extreme pressure or temperature applications. Overkill for most residential installations but used in commercial settings.

Care Tips to Extend Housing Life

• Handle carefully — avoid dropping or banging the housing bowl; cracks cause leaks
• UV exposure — always use blue (opaque) bowls in any location with sunlight exposure
• Freezing — never allow the housing to freeze; ice expansion cracks plastic housings
• Chemical exposure — keep away from aerosol sprays, cleaning products, and insecticides
• Pressure — never exceed the housing’s maximum pressure rating; install a pressure reduction valve if mains pressure is high
• O-ring maintenance — lubricate the O-ring with food-grade silicone grease at every cartridge change to maintain a leak-free seal

When to Replace the Housing Bowl

Plastic housing bowls have a finite service life regardless of how well they’re maintained:

• Clear bowls: replace every 5 years
• Blue/opaque bowls: replace every 10 years

Write the installation date on the bowl with a permanent marker so you don’t lose track. Replace sooner if you notice any cracks, crazing, discolouration, or if the housing develops a persistent leak that O-ring replacement doesn’t fix.

Install filter housings where a leak won’t cause property damage — near a floor drain or in a garage/laundry where water can drain safely.

What Comes with a Housing Kit?

Most housing kits include: one installed O-ring + one spare O-ring, mounting bracket and hardware, and a filter bowl wrench. Keep the spare O-ring somewhere accessible — you’ll need it at the next cartridge change.

Frequently Asked Questions