Whole-house water filter, North Bondi

The owner of this North Bondi house already had a water filter. It was an old twin-canister unit hanging off the pipes in the basement, and she had stopped trusting it. Her worry was chemicals in the mains water, and she wanted to know what the best whole-house water filter for her home would actually be. She didn't want the cheapest option.

She had spoken to more than one filtration company before we came out, and she came with good questions. What does it reduce, what doesn't it, and where does it go. This post walks through the answers and the install.

What went in at the North Bondi house

The system is a Puretec FilterWall F5. It's a three-stage whole-house water filter in a lockable powder-coated cabinet, with a built-in bypass so the house never has to go without water during a cartridge change. Stage one is a washable sediment cartridge, stage two a finer sediment cartridge, and stage three a carbon block.

Puretec make four models in the F Series. The F5 is the larger of the two built for soft water, which is what Sydney has. The F6 adds a scale reduction cartridge, but Sydney's supply sits well inside the soft range, so in an Eastern Suburbs home that stage is solving a problem the house doesn't have. You can look up the tested hardness for your own area on Sydney Water's water analysis page.

Installing a whole-house water filter under the house

Most FilterWalls we install stand outside against a fence or along a side passage. This one went under the house instead.

Like a lot of older North Bondi homes, this house sits on sandstone, and the incoming copper main runs through the basement below the floor. That's where the old filter was, and it was the right place for the new one. It's out of the weather, out of sight, and directly on the main before it branches off to anything in the house.

Here's what the install involved:

• Disconnected and removed the old filter unit.
• Mounted the FilterWall on the sandstone basement wall in the same spot, fixed to a batten so the cabinet sits square on uneven stone.
• Altered the existing 25mm copper pipework to run into and out of the new unit.
• Fitted a pressure limiting valve, set to 500 kPa.
• Commissioned and tested the system, checked every joint, then ran water through to every tap.

Why we fitted a pressure limiting valve

Mains pressure in parts of the Eastern Suburbs can run higher than a house needs, especially on low ground near the coast. The plumbing standard (AS/NZS 3500) caps static pressure at outlets inside a home at 500 kPa, and high pressure is hard on tapware, flexi hoses, hot water systems and filter housings alike.

So the valve went in alongside the filter, set to 500 kPa. It isn't the exciting part of the job, but it protects the new system and everything downstream of it.

What a whole-house water filter actually reduces

This was the owner's main question, so it's worth being exact.

On Puretec's specification, the FilterWall F Series reduces chlorine by up to 98%, along with sediment and the impact of scale. Puretec also list the F5 among their systems for reducing PFAS, the group of compounds usually called forever chemicals, through its activated carbon.

Puretec describe the day-to-day benefits as softer hair, less irritated skin, softer laundry, protected appliances and less plastic waste from bottled water. Because the filter sits on the main, that covers the shower, the laundry and the garden tap, not just the kitchen.

Cartridges and the first service

Puretec specify a cartridge change every 6 to 12 months, depending on how much water the household uses and what comes through the main. The FilterWall uses standard 20-inch cartridges, and genuine Puretec replacements are carried by plenty of suppliers. You aren't locked into buying them from one company.

The owner bought a spare premium cartridge kit with the install, and Norton Plumbing will come back at 10 to 12 months to fit it and service the system at no charge. The unit has Puretec's 10-year warranty: one year parts and labour, nine years parts, cartridges excluded. Our own workmanship warranty sits on top of that.

Signs your old whole-house filter needs replacing

Plenty of older Bondi and North Bondi houses have a filter in the basement or under the house that was fitted years ago and then forgotten. These are the signs it's time to look at it:

• You can't find cartridges for it, or nobody knows when they were last changed.
• The housings are corroded or weeping at the joins. That's common in salty coastal air under a house.
• There's no bypass, so changing a cartridge means shutting the water off to the whole house.
• The chlorine taste is back at the kitchen tap or the smell is back in the shower.

How to reach Norton Plumbing

Norton Plumbing is a family-owned Eastern Suburbs plumbing business and a Puretec Specialist Plumber. Adam Norton holds NSW plumbing licence 397768C and does the filtration assessments himself. Call 0477 858 951 to book a free visit. We'll look at where the main runs, what's there now and what suits the house. Read more on water filtration and plumbing in Bondi.