Water Softeners for the Home: How to Choose in Australia

Start with how softening works, because it explains the running costs and the rules below. Then check hardness, sodium, plumbing, disposal and certification before you compare models.

• How it works: a typical household softener uses ion exchange. It removes the hardness minerals calcium and magnesium and replaces them with sodium, usually supplied by dissolved salt (brine).^[1]
• Inside the unit, water passes through a bed of resin beads. Calcium and magnesium stick to the beads and the loosely held sodium is released into the water.^[1]
• Regeneration: when the resin is full, the unit cleans it with salt brine. The sodium in the brine swaps places with the calcium and magnesium on the resin, and the excess is flushed out as wastewater.^[1]
• Know your hardness type: total hardness is split into carbonate hardness and noncarbonate hardness, and noncarbonate hardness is the difference between the total and the carbonate figure. A water test that gives both figures tells you more than a single number.^[2]
• Salt use: the amount depends on the number of people in the household, daily water use, the softener's capacity and how hard the water is. A bigger household or harder water means more salt over a year.^[1]
• Water use: one regeneration uses roughly 50 gallons of water according to a US university extension guide. That is about the same as a load of laundry in an older washing machine, or two loads in a high-efficiency one.^[1]
• Sodium added: softening adds about 8 mg/L of sodium for each grain per gallon (gpg) of hardness, so the harder your water, the more sodium is added.^[1]
• Low-sodium diets: food is the major source of sodium. The average Australian dietary intake is estimated at about 4 g a day, and low-sodium diets may limit it to under 2 g a day. Water supply makes only a modest contribution, but guidance still encourages keeping water sodium as low as possible.^[3]
• Alternative salts: the Australian Drinking Water Guidelines (NHMRC) encourage steps to cut sodium, such as using alternative salts in domestic softeners, because sodium cannot easily be removed from drinking water. If you are on a restricted diet, ask your doctor and the seller about this before buying.^[3]
• Connections: compare the inlet size and drain fitting with your pipework. One Australian retailer listing shows a 1-inch male BSPT inlet (a tapered pipe thread) and a half-inch drain connection. Match these details on any model you consider.^[4]
• Backflow protection: Barwon Water (Victoria) describes individual protection as installing a backflow prevention device at the point where the water pipes connect to a fixture or appliance.^[5]
• Testable devices: Barwon Water's policy requires a testable backflow prevention device at or near the property boundary for medium or high hazard properties, installed in accordance with AS/NZS 3500.1 and the Plumbing Code of Australia, with no connection bypassing it. Its policy also has property owners agree to maintain and test the device at intervals of no more than 12 months, or as Barwon Water determines. That interval is Barwon Water's term, not a general rule.^[5]
• Plumbing standard: the Victorian Building and Plumbing Commission says a backflow protection device must be installed as specified in Section 4, and that plumbing work commenced on or after 20 October 2025 must comply with the 2025 version of the standard. Ask a licensed plumber which requirements apply to your property, and confirm current rules with your state regulator and local water authority.^[6]
• Disposal to sewer: Byron Shire Council (NSW) says any business that lets waste water other than domestic sewerage into a Council sewer must apply for liquid trade waste approval. It also lists substances that must not go into the sewerage system or a pre-treatment system. That rule is about businesses, and it does not say whether home softener discharge is restricted, so ask your own council or water authority.^[7]
• Approval and penalties: the same council says plumbing approval is required to install liquid trade waste pre-treatment equipment, and unapproved or non-compliant discharge may lead to higher disposal costs and fines.^[7]
• Certification: a material or product in contact with drinking water must comply with AS/NZS 4020 under Part A of the Plumbing Code of Australia, according to the WaterMark scheme site. Ask the seller for proof of this for the softener and any fittings.^[8]
• Checking the listing: the WaterMark Schedule of Products lists the plumbing and drainage products included in the WaterMark Certification Scheme. Use it to see whether a product type needs certification.^[8]

For who may install a softener, see our general water softeners buying guide.

1. [1]Unl (checked 2026-11-12)
2. [2]Hardness (as calcium carbonate) (checked 2026-11-11)
3. [3]Sodium (checked 2026-11-12)
4. [4]Puretec SOL40-E3 Water Softener (checked 2026-11-12)
5. [5]OFFICIAL OFFICIAL Backflow Prevention and Containment Policy Guidelines (checked 2026-11-11)
6. [6]Updated plumbing and drainage standards - Part 1: Water services (checked 2026-11-12)
7. [7]Approval to discharge liquid trade waste (checked 2026-11-12)
8. [8]Schedule of Products - WaterMark Certification (checked 2026-11-12)

Drafted with AI assistance from the sources listed, then fact-checked and edited by the PouchMe team. PouchMe researches products from published information; we have not tested them ourselves.