Choosing the right filters for tank water

Match the filter to the job

• Garden and toilet use asks little of the water.
• Washing and showering wants it clear and free of grit.
• Drinking and cooking is where it’s worth doing properly: clear, clean and safe.

The layers, coarse to fine

• Sediment filter (spun or pleated): the workhorse, catches grit, silt and debris, usually rated in microns (a lower number is finer).
• Carbon filter: improves taste and smell and grabs some chemicals; a common second stage.
• Fine or absolute-rated filter: a tighter micron rating for finer particles.
• UV or a proper drinking-water setup: where you want to be sure the water is safe to drink, an ultraviolet unit is the usual step, on already-clear water, because UV needs the water clear to work.

How to choose

Start with the use. A simple sediment filter protects your pump and appliances and clears the water for washing. Add carbon for taste. For drinking water, treat sediment first, then polish, then disinfect (commonly UV), in that order, as each stage protects the next. Check the micron rating and the flow rate so the filter keeps up with your household without choking your pressure.

Common questions

Which way around do the filter housings go?

Follow the IN and OUT marks on each housing head; they must match the direction of flow. A housing plumbed backwards clogs fast and filters poorly.

What micron rating do I need?

For general sediment, 5 to 20 micron is common; finer (1 micron or below) is used ahead of drinking-water treatment. Finer isn’t always better, as too fine a filter clogs fast and drops your pressure. Match it to the job.

Does tank water need UV?

If you drink it and want to be confident it’s safe, disinfection such as UV is the usual step, after the water has been filtered clear. For garden or laundry use it’s generally overkill.