Water Filter Deals Australia: Black Friday and Prime Day

Amazon Australia’s Prime Big Deal Days sale opens on 29 September 2026 and runs to 5 October. Black Friday falls on 27 November, and the Boxing Day sales start on 26 December. Those three windows are when most Australians buy a water filter, and when the cartridge multipacks that keep a filter working get their deepest cuts of the year. A household that drinks 1.2 litres a day from a Brita jug uses twelve cartridges a year, so a sale that discounts the twelve-pack once is worth more than a cheap jug.

This page is our standing guide to water filter deals in Australia. It sets out the sale calendar, what actually gets discounted and what rarely does, which filter and cartridges to buy for your city’s water, and how to tell a real deal from a sale sticker. We update it before each event. The picks come from the utility readings behind WaterScore’s suburb pages, not from whatever is on the front page of the sale.

Australian Water Filter Sale Calendar

Event	When	Who can shop it	What to expect on water filters
Amazon Prime Big Deal Days	29 September to 5 October 2026	Prime members	Jug starter packs and cartridge multipacks. Amazon is running it a week earlier than in 2025
Amazon Black Friday sale	Black Friday is 27 November 2026. In 2025 Amazon’s sale opened on 18 November and ran to 1 December	Everyone	The year’s widest range of filter discounts, including under-sink and reverse osmosis systems
Cyber Monday	30 November 2026	Everyone	Mostly the same deals as Black Friday. By then stock, not price, is the risk
Boxing Day	26 December 2026 into early January	Everyone	Retailer clearance. Fewer filter deals than November, and better on appliances than on cartridges
End of financial year	June 2027	Everyone	Broad retailer sales. Cartridge discounts are less common than in November
Amazon Prime Day	Mid-July. In 2026 it ran from 7 to 13 July	Prime members	The winter equivalent of Black Friday for brands that sell mainly through Amazon

Amazon announces exact dates two to three weeks out and we update this table when it does. The two Amazon events are where most water filter deals on cartridges land, because Brita, ZeroWater, Waterdrop and iSpring all sell their multipacks and replacement sets there. The Prime Big Deal Days page and the Black Friday page go live a few days before each event starts.

What Actually Goes on Sale

Sale pages are built around headline appliances, and water filter deals follow a pattern that has held for several years.

Jugs and starter packs are the loss leaders. A Brita Marella with one cartridge, or a ZeroWater jug with its TDS meter, is cheap to discount and gets you into the brand’s cartridge system. Buy one if you need one, but the jug is not where the money is.

Cartridge multipacks are the real prize. Brita’s Maxtra Pro six- and twelve-packs, ZeroWater’s replacement filter packs and Philips Micro X-Clean multipacks are the subscription cost of a jug, and the multipacks are where the deepest cuts land. Twelve months of cartridges bought in one sale is the single biggest saving available on a filter.

Under-sink and reverse osmosis systems go on sale at Black Friday and Prime Day, and less often in between. Waterdrop and iSpring sell mainly through Amazon and price their systems for the events. Their annual replacement filter sets are discounted less often than the systems, so buy the system in the sale and expect to pay closer to full price for the filters later.

Whole-house descalers rarely move. Products such as the AO Smith salt-free descaler come from a small number of sellers and the price barely changes across the year. If a descaler is the right fix for your water, waiting for a sale usually gains you nothing.

Test kits and TDS meters are cheap all year. They often appear as add-on deals. A TDS meter is worth having anyway if you run a ZeroWater jug or a reverse osmosis system, because it tells you when the filter is exhausted rather than leaving you to guess from taste.

Amazon’s Subscribe and Save applies a standing discount to repeat cartridge orders outside the sales. Check whether the event price on a multipack beats it before locking in a subscription, and remember that a subscription keeps delivering after your sale stock runs out, which is the point of it.

Water Filter Deals by Water Type

The right deal depends on what is in your tap water, and that varies more across Australia than most sale roundups admit. Melbourne’s supply runs as soft as 8 mg/L hardness. Adelaide’s metro supply sits between 87 and 136 mg/L and regional South Australia reaches 602 mg/L. Sydney and Brisbane disinfect with chloramine, which a small jug cartridge reduces more slowly than free chlorine. Check your suburb on WaterScore first, then buy from the row that matches.

Your water	Cities	What to buy in the sale	Cartridges to stock
Soft, free chlorine	Melbourne, Hobart, Launceston, Canberra, Gold Coast, Darwin, most of Perth metro	BRITA Marella 2.4 L jug (Budget-friendly)	Maxtra Pro twelve-pack
Soft to moderate, chloramine	Sydney, Brisbane	BRITA Marella jug, or the Waterdrop TSA under-sink filter (Mid-range) if the taste comes back before the cartridge indicator says so	Maxtra Pro twelve-pack, or the TSA replacement set
Hard, scale in the kettle	Adelaide, northern Perth, regional SA and WA, Alice Springs	iSpring RCC7AK reverse osmosis (Premium) for drinking water, and the AO Smith salt-free descaler (Premium) for the hot water system	RCC7AK annual filter set
Fluoride or PFAS is the reason you filter	Any city	ZeroWater 2.8 L 5-stage jug (Budget-friendly) or the Waterdrop TSA under-sink filter (Mid-range)	ZeroWater replacement filters
Renting, tank water or off-grid	Any	Purewell 8.5 L gravity system (Mid-range), or the Waterdrop WD-C1H countertop reverse osmosis (Premium), neither of which touches the plumbing	Purewell replacement elements

Budget-friendly, Mid-range and Premium are our editorial labels. Amazon changes prices during an event, sometimes daily, so we do not print dollar figures here. Every pick is reviewed in full in our guide to the best water filters for Australian tap water, the supermarket alternatives are covered in the Coles water filter jugs guide, and the no-plumbing options in the best water filter for renters.

City ranges come from the utility readings on WaterScore’s suburb pages, and your suburb can sit anywhere inside them. Perth is the clearest case: most metro suburbs read between 14 and 130 mg/L, while northern suburbs pass 200 mg/L and belong in the hard-water row. The Adelaide and Perth filter pages show the suburb-by-suburb split.

Stock a Year of Cartridges

Cartridge maths is what turns a sale into a saving. Work out how many you use in a year, then buy that many in one event, because the per-cartridge price of a multipack on sale is usually the lowest you will see all year.

Filter	Rated life	A household drinking 1.2 L a day needs	Buy in the sale
Brita Maxtra Pro (jug)	150 litres or 4 weeks, whichever comes first	12 to 13 cartridges a year	One twelve-pack
ZeroWater 5-stage (jug)	Until the meter reads 006 ppm. About 150 litres in water under 50 ppm TDS, 30 to 60 litres above 300 ppm	About 3 a year in Melbourne, 8 or more in Adelaide	A multipack sized to your TDS reading
Waterdrop TSA (under-sink)	Three cartridges on roughly 6, 12 and 18 month cycles	One replacement set every year or so	One set
iSpring RCC7AK (reverse osmosis)	Pre-filters and post-filters every 6 to 12 months, membrane every 2 to 3 years	One annual filter set	One set, and the membrane separately when it is due
Purewell gravity elements	Several thousand litres per element	One set every year or two	One set of elements

The ZeroWater row is why a TDS meter matters. The filter is rated by the meter reading, not by the calendar, and its life collapses in high-TDS water. Melbourne and Hobart households get months from a filter. Adelaide households, on the metro supply’s 300 ppm and more, change it every few weeks, and at that rate a reverse osmosis system is cheaper to run within the first year.

Storage is not a problem for a year’s supply. Brita says sealed cartridges keep for several years between 1 and 50 degrees Celsius and out of direct sunlight. A used cartridge is different. The four-week limit is a hygiene rule as much as a capacity one, because a damp carbon bed left in the jug for months starts to grow things. Buying more than a year ahead is also a bet on the jug: Maxtra Pro fits the jugs that took Maxtra+, but there is no promise the next cartridge will.

How to Tell a Real Water Filter Deal

1. Check the price history, not the strike-through. A “was” price only means something if the product actually sold at that price recently, which is the test the ACCC applies to two-price advertising. Keepa and CamelCamelCamel both track Amazon Australia. A Black Friday price that matches the July Prime Day low is a real water filter deal. One that matches last week’s price is a sticker.

2. Compare per cartridge, not per pack. Divide the pack price by the number of cartridges. A twelve-pack at a small discount can beat a six-pack at a large one, and a supermarket half-price week on four-packs sometimes beats both.

3. Match the cartridge to the jug. Maxtra Pro fits the Brita jugs that took Maxtra+. ZeroWater’s 5-stage filter fits all of its jugs and dispensers. Waterdrop and iSpring replacement sets are model-specific, so check the model number on the listing rather than the photo.

4. Check the seller and the warranty. For a reverse osmosis system, buy from the brand’s own Amazon store or from Amazon itself, so the warranty and the replacement filters line up. A third-party import of the same model may ship with filter sizes you cannot buy here.

5. Do not let the discount change the filter type. A cheap reverse osmosis system is still the wrong tool for Melbourne’s soft water, and a cheap jug still does nothing for scale in Adelaide. Our guide to reverse osmosis versus carbon filters explains which problem each one solves.

What You Can Do

1. Check your suburb’s readings first. Search your suburb on WaterScore for its hardness, chlorine and fluoride values. Under 60 mg/L hardness with a chlorine complaint means a jug and a year of cartridges. Over 120 mg/L means reverse osmosis for drinking water and a descaler for the house.

2. Put the dates in your calendar. 29 September for Prime Big Deal Days, mid-November for the start of Amazon’s Black Friday sale, and 26 December. Set a reminder a week before each one, which is when we refresh this page with the water filter deals Amazon has confirmed.

3. Count your cartridges. Use the table above to work out a year’s supply. The water hardness calculator converts your suburb’s reading into the units on cartridge packaging and estimates how quickly a jug cartridge exhausts in your water.

4. Add the multipack to your Amazon cart a week before the event. Amazon flags the price change on cart items when the sale starts, so you can see the real discount against the pre-sale price without opening a price tracker.

5. Compare suburbs before buying a reverse osmosis system. The suburb comparison tool shows how your suburb’s hardness compares with neighbours on a different supply zone, which is often the difference between a jug being enough and not. If you are still unsure, the hard water versus soft water guide explains what the readings mean for a kettle and a hot water system.

Frequently Asked Questions

When is the best time to buy a water filter in Australia?

Amazon’s Black Friday sale in the second half of November has the widest range of discounts on jugs, under-sink filters and reverse osmosis systems. Prime members get an earlier run at cartridge multipacks in Prime Big Deal Days, which runs from 29 September to 5 October in 2026. Supermarket half-price weeks on Brita four-packs happen through the year and are worth comparing per cartridge.

Are water filter cartridges cheaper on Black Friday?

Usually, and mostly on multipacks. Six- and twelve-packs of Brita Maxtra Pro and ZeroWater replacement filters carry the deepest cuts during Amazon’s Black Friday sale and its Prime events. Divide the pack price by the number of cartridges and compare it with the supermarket half-price four-packs, and check a price tracker before trusting a strike-through price.

How long can I store unused Brita cartridges?

Brita says sealed cartridges in their original packaging keep for several years if stored between 1 and 50 degrees Celsius and out of direct sunlight. Once a cartridge is in the jug it is rated for 150 litres or four weeks, whichever comes first. A twelve-pack bought in one sale is well within the storage guidance for a household that changes monthly.

Is Prime Big Deal Days worth it for water filter deals?

If you already have Prime and run a jug, yes. The 2026 event runs from 29 September to 5 October and is the first chance to stock cartridge multipacks before summer. Joining Prime just to buy cartridges rarely pays for itself, and non-members get most of the same filter deals in Amazon’s Black Friday sale in November.

Should I buy a reverse osmosis system or a jug in the sale?

Buy for your water, not for the discount. Hardness above 120 mg/L, or a wish to remove fluoride or PFAS, points to reverse osmosis or a ZeroWater jug. Soft, chlorinated water in Melbourne, Hobart, Canberra or the Gold Coast is best served by a Brita jug and a year of cartridges. A discounted reverse osmosis system is still the wrong tool for soft water, and a cheap jug still does nothing for kettle scale.

Do Coles and Woolworths have Black Friday water filter deals?

Both chains list Black Friday specials, but their best Brita prices are the half-price weeks on four-packs that run through the year. The jug is the same product at both. Compare the supermarket four-pack per cartridge with an Amazon six- or twelve-pack in the sale, and buy whichever is cheaper per cartridge that week.

Summary

Water filter deals in Australia cluster in three windows: Prime Big Deal Days from 29 September, Amazon’s Black Friday sale through the second half of November, and Boxing Day. The jug is the loss leader and the cartridges are the saving, so buy the filter that suits your suburb’s water, stock a year of cartridges in whichever event you can shop, and check the price history before trusting the sale sticker. We refresh this page before each event with the dates Amazon confirms.

Sources

1. Amazon Australia, Prime Big Deal Days, event page stating 29 September to 5 October 2026, accessed September 2026. amazon.com.au
2. Amazon Australia, Amazon’s Prime Day returns July 7–13 with unmissable offers for Aussie shoppers, media release, 2026. amazonau.gcs-web.com
3. Tom’s Guide, Amazon Black Friday sale 2025 is now on, reporting the 18 November to 1 December 2025 sale period, 2025. tomsguide.com
4. BRITA Australia, Frequently asked questions, MAXTRA PRO replacement interval and cartridge storage, accessed September 2026. store.brita.com.au
5. Culligan with ZeroWater Technology, Support: filter life by TDS level, accessed September 2026. shop.culligan.com
6. iSpring Water Systems, Replacement water filter set for RCC7AK and RCC7P-AK, replacement schedule, accessed September 2026. ispringfilter.com
7. Australian Competition and Consumer Commission, Advertising and selling guide: Two-price comparison advertising, ACCC, Canberra. accc.gov.au
8. CHOICE, Everything you need to know for Black Friday and Cyber Monday, CHOICE, 2025. choice.com.au
9. National Health and Medical Research Council, Australian Drinking Water Guidelines 6, Version 3.9, NHMRC, Canberra, 2024. nhmrc.gov.au