Alternatives to Harvey Water Filter Cartridges: Check the Fitting
Compare Omnipure Q5536, Q5586 and Harvey-compatible screw-in cartridges, and check the fitting before buying a replacement.
For a Harvey screw-in drinking-water filter, Omnipure Q5536 and Q5586 are alternatives listed as compatible by Filter Flair. That recommendation does not cover Harvey TwistLock filters. TapSparesUK also offers a Harvey-compatible screw-in cartridge and explicitly warns that it is not the TwistLock version. (Filter Flair compatibility guide, TapSparesUK cartridge listing)
These are replacements for the drinking-water filter under the sink—not parts for the water softener itself.
Identify your Harvey fitting first
Harvey sells separate screw-in and TwistLock cartridges. Its published measurements are:
- Screw-in: 26.5 cm long, 6.2 cm fixing diameter and 5 cm internal fixing diameter.
- TwistLock: 27.5 cm long, with the same published fixing diameters.
The similar diameters make size alone a poor compatibility check. Match the cartridge label, head model and connection style; Harvey specifically asks buyers to check the fitting before ordering. (Harvey screw-in specifications, Harvey TwistLock specifications)
If identification is uncertain, send the supplier photographs of the installed head and cartridge label. Ask it to confirm compatibility with that head, rather than just with “Harvey filters”. Do not remove a pressurised cartridge merely to photograph its connection.
Alternatives for the screw-in version
| Alternative | What it offers | When to replace it |
|---|---|---|
| Omnipure Q5536 | Coconut carbon for chlorine, taste and odour reduction; an option when you do not need scale-inhibition media | Filter Flair recommends 12 months. Replace sooner if the manufacturer’s rated 2,000-gallon capacity is reached or flow becomes too slow. (Supplier comparison, manufacturer sheet) |
| Omnipure Q5586 | Granular activated carbon plus phosphate scale-inhibition media | Six months or 5,680 litres, whichever comes first—or sooner if flow becomes too slow. (UK listing, manufacturer sheet) |
| TapSparesUK HARVGAC, 10-inch screw-in | GAC cartridge explicitly sold for Harvey screw-in filter-tap systems; no scale reduction | Supplier lists a 12-month life and dimensions matching Harvey’s published screw-in measurements. (HARVGAC listing) |
Compare annual cost, not just cartridge price. A six-month Q5586 normally means buying two cartridges per year. As of 6 November 2026, TapSparesUK listed HARVGAC at £37 with free UK delivery, versus £59.95 including VAT and delivery for Harvey’s own screw-in cartridge—a £22.95 difference per purchase. (TapSparesUK price, Harvey price)
Physical compatibility is not proof of identical filtration. The Omnipure sheets document Standard 42 chlorine, taste and odour performance; they do not establish lead or fluoride reduction. The Q5586’s additional feature is scale inhibition, not a documented hardness-removal claim. For treatment beyond taste adjustment, compare the exact reduction claims using our carbon-filter selection guide. (Q5536 performance data, Q5586 performance data)
If yours is TwistLock
Do not order Q5536, Q5586 or HARVGAC solely because a listing mentions Harvey or TwinTec. The compatibility recommendation above is for screw-in fittings. For a cartridge-only change, use a matching Harvey TwistLock cartridge unless another supplier explicitly confirms its substitute fits your exact TwistLock head.
Moving to a different cartridge family means assessing a replacement head or complete filter system—not forcing a screw-in cartridge into the existing fitting. For example, Filter Flair’s Q5586 system includes its own Q-series head with ¼-inch push-fit connections. Those connections must be checked against your existing tubing and tap plumbing before considering a conversion. (Q5586 system components)
For any replacement, isolate the water supply, follow the instructions supplied with the actual cartridge and head, flush as directed, and check for leaks before leaving it in service. (Omnipure replacement guidance, Harvey TwistLock instructions)