- What it does: Filters every drop of water entering your home — all taps, showers, appliances
- Installed cost: $900–$4,500 depending on system stages and site access
- Best for: Tank/bore/rainwater users, chlorine-sensitive households, high sediment water
- Not a replacement for RO: Whole house carbon filters don't remove fluoride or PFAS — combine with under-sink RO for drinking water purity
- Requires: Licensed plumber, accessible mains connection point, WaterMark certified products
- Annual maintenance: $200–$430 for cartridge replacement
What a whole house filter actually is
A whole house (point-of-entry) water filter is installed at the mains water entry point to your property — typically in the garage, utility cupboard, or under the house near where the water main enters. Every litre of water that flows to any tap, shower, bath, dishwasher, washing machine, or garden tap passes through the filter first.
This distinguishes it from under-sink and benchtop filters (point-of-use systems) which only treat water at a single tap. Whole house filtration means filtered water from your shower, which reduces chlorine absorption through skin and inhalation of chlorine vapour during hot showers — a concern for chemically sensitive households.
Who actually needs a whole house filter
✓ Strong case for whole house
- Tank, rainwater, or bore water (unregulated, needs sediment + UV)
- High sediment causing scale on shower screens and appliances
- Sensitive to chlorine — skin reactions, asthma triggered by shower steam
- Hard water areas (Perth especially) — scale on appliances and fixtures
- Rural properties where water quality varies seasonally
- Wanting filtered water from every tap without multiple point-of-use units
⚠️ Consider alternatives first
- Town mains water, only concerned about drinking water taste → under-sink carbon filter is sufficient and much cheaper
- Fluoride or PFAS removal → whole house doesn't help, need under-sink RO
- Renting → whole house installation not appropriate, use benchtop or under-sink
- Tight budget → under-sink filter delivers most of the benefit for drinking water at a fraction of the cost
Whole house system configurations
2-stage: sediment + carbon
Stage 1: 5-micron sediment filter removes rust, sand, dirt. Stage 2: Carbon block or GAC removes chlorine, chloramines, taste and odour. The standard setup for town mains water. Good flow rate, reasonable maintenance cost. Installed cost: $900–$1,800. Best for: town water with taste/chlorine concerns.
3-stage: sediment + carbon + UV
Adds a UV disinfection stage that kills 99.99% of bacteria and viruses. Essential for tank, rainwater, or bore water. UV doesn't remove chemical contaminants — the carbon stage handles those. Installed cost: $1,400–$3,000. Best for: any non-mains water source, or mains water in areas with biological contamination history.
Advanced: PFAS / hard water / iron
Specialist stages for specific problems: activated carbon NSF P473 certified for PFAS removal, ion exchange resin for hard water softening, oxidising media for iron and manganese removal. Requires water testing first to specify correctly. Installed cost: $2,000–$4,500+. Best for: specific identified water quality issues confirmed by testing.
Installation requirements
Whole house filter installation is more involved than under-sink — it requires interrupting your main water supply and working with larger diameter pipes. Always use a licensed plumber.
- Accessible mains location: The plumber needs to identify and access your main water entry point. In older homes this may be under a slab requiring jackhammering — add $500–$1,500 for difficult access.
- Bypass valve: A properly installed whole house system should include a bypass valve so you can isolate the filter for maintenance without cutting water to the whole property.
- Space for filter housing: Standard 10-inch filter housings are 12–15cm diameter and 30–40cm tall. The installation location needs to be accessible for cartridge changes every 3–6 months.
- UV power supply: If including UV, a 240V power outlet must be within reach of the UV unit. Budget for an electrician if one isn't already positioned nearby.
- Pressure consideration: Some systems reduce water pressure slightly. A pressure regulator or booster pump may be required for properties with low mains pressure.
What it costs
| System Type | Unit Cost | Installation | Total Installed | Annual Maintenance |
|---|---|---|---|---|
| 2-stage (sediment + carbon) | $300–$600 | $500–$900 | $800–$1,500 | $200–$280 |
| 3-stage (+ UV) | $600–$1,200 | $600–$1,100 | $1,200–$2,300 | $250–$380 |
| Premium (PFAS / hard water) | $1,200–$2,500 | $800–$1,500 | $2,000–$4,000 | $300–$500 |
| Under-slab access (add-on) | — | $500–$1,500 extra | Varies | — |
Yes — this is the recommended combination for households wanting comprehensive water quality. The whole house system handles sediment, chlorine, and general water quality for all taps and showers. The under-sink RO provides high-purity drinking and cooking water at the kitchen tap — removing fluoride, PFAS, heavy metals, and anything the whole house filter doesn't catch. Combined cost: $2,000–$5,500 installed, depending on system grades.
Sediment pre-filters: every 3–6 months (more frequently if your water has visible sediment). Carbon filters: every 6–12 months. UV lamps: annually (even if the lamp still appears to glow — UV intensity degrades over time). Set calendar reminders — whole house filters process much higher water volumes than under-sink filters and cartridges exhaust faster than expected.