Which Water Filter Do I Need? A Guide by Water Source

Puretec whole house filters for mains water and UV filters for rainwater

Start with your water source, then your goal. Mains (town) water usually calls for carbon filtration to reduce chlorine, taste and odour; rainwater needs filtration plus UV to deal with bacteria; bore and river water should be tested first because the contaminants vary. Then decide whether you want filtered water at one tap (under-sink) or every tap (whole-house), and size the system to your home.

Step 1: your water source

Water source	Common concerns (Puretec)	Typical Puretec approach
Mains / town water	Chlorine taste and odour, sediment, chemicals including PFAS, hardness	Whole-house carbon (FilterWall F, WH2) and/or under-sink Z series; a softener or F4/F6 for hard water
Rainwater tank	Bacteria, sediment, taste and odour, low pH, tannin	Filtration plus Radfire UV (Hybrid E, Hybrid M1); EM2 filters with TankSafe; NTS neutraliser for low pH
Bore water	Iron, hardness, nitrate, bacteria	Water test first, then treatment such as IronStop, NTR or softening before filtration and UV
River / surface water	Sediment, tannin, suspended solids, bacteria	Water test first; multi-stage packages with sediment, tannin and UV stages

Step 2: your goal

Better-tasting drinking water – an under-sink carbon filter such as the PureMix Z7 or Z6. See our chlorine guide.
Reducing chemicals including PFAS – whole-house carbon, with an under-sink carbon or RO filter added for drinking water.
Fluoride or nitrate reduction – reverse osmosis such as the RO270.
Bacteria and cysts – UV (Hybrid systems) or ultrafine 0.1 micron (nominal) filtration. See our rainwater guide.
Scale and spotting – FilterWall F4/F6 scale reduction or a Softrol water softener.

Step 3: one tap or the whole house?

An under-sink filter treats the water at one tap, usually for drinking and cooking. A whole-house filter treats all water entering the home, so you also shower in filtered water and protect appliances. Our under-sink vs whole-house guide compares them in detail.

Step 4: size it to your home

Puretec matches systems to household size and flow:

FilterWall F3/F4 (10″) for small to medium homes; F5/F6 (20″) for homes with 2+ bathrooms.
WH2-30 for 1–2 bathrooms; WH2-55 for 2+ bathrooms.
Hybrid E6 for homes with 1 bathroom; Hybrid E7 and E13 for 2+ bathrooms.

When to test first

Puretec requires a water test before buying a system for surface or bore water, and strongly encourages confirming any selection because water chemistry is complex. Its Water Analysis Test Kit is a mail-in test covering parameters such as pH, hardness, iron, nitrate and fluoride, with tailored recommendations.

Installation: connection to your water supply must be carried out by a licensed plumber, and any hard-wired electrical work by a licensed electrician.

Frequently asked questions

Do I need to test my water before buying a filter?

For bore and surface water, Puretec says a water test is needed before purchase. For mains and rainwater a test is not always required, but it helps confirm the right system.

Can one filter fix every water problem?

Rarely. Puretec notes water chemistry is complex and strongly encourages confirming product selection, sometimes with a water analysis. Problems such as iron, nitrate or high hardness need dedicated treatment.

Can I use a rainwater filter on other water sources?

Some can. Puretec says its EM2 series is designed for rainwater but can also be used on mains, river, dam and bore water, and recommends seeking its advice before purchase.