Compare the essentials, not the slogans.
Choose the format first; use the live price as the final check.
This table reflects Waterdrop-reported technical details checked on 13 November 2026, not measurements made by TapFilterChoice. Specifications and filter compatibility must be confirmed at the retailer before purchase.
| Question | G3P600 | M6SL | M6HG |
|---|---|---|---|
| Where it goes | Under sink | Countertop | Countertop |
| Installation | Water feed, drain, power and dedicated faucet | Manual tank filling, electricity | Manual tank filling, electricity |
| Instant hot dispensing | No | No | Yes, multiple temperatures |
| Rated capacity | 600 GPD | 75 GPD | 75 GPD |
| Stated product-to-drain ratio | 2:1 | 3:1 | 3:1 |
| Dimensions (W × D × H, cm) | 46.0 × 14.4 × 45.0† | 40.3 × 23.5 × 36.9† | 40.39 × 23.62 × 36.83† |
| Replaceable filter types | CF, CB and RO | M6RFL | M6RFG |
| Retailer-listed annual filter estimate | Depends on three cartridge cycles | ~£69.99 | ~£69.99 |
| Best fit | Dedicated tap, higher throughput | No plumbing, room-temperature use | No plumbing, hot-water dispensing |
† Manufacturer lists three dimensions in this order; verify which face corresponds to width/depth at the point of installation. GPD is an output-capacity rating, not a promise of actual household usage.
Which one would we shortlist?
G3P600 if a dedicated installation makes sense
You gain the convenience of water from a separate tap and avoid manually replenishing a countertop tank. In exchange, you need clearance, power, a drainage connection and three replacement-filter schedules.
M6SL if your kitchen is temporary or you want no plumbing
A reasonable candidate for renters, subject to the lease and space. You refill its reservoir, need a nearby socket and handle the separated waste water. It is not an instant-hot appliance.
M6HG if hot dispensing is a feature you will actually use
Hot dispensing can replace part of your kettle routine, but it adds an appliance function and another reason to verify energy use. Compare the premium against the M6SL.
Do not ignore a simpler carbon filter
If your goal is primarily to change the flavour or smell of otherwise compliant tap water, a cheaper, easier-to-maintain carbon filter might be enough. Our RO vs carbon guide explains this limitation.
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Retailer campaign prices — checked 13 November 2026
Listed on Waterdrop UK’s promotional page, not continuously monitored. Crossed-out prices are the retailer’s own reference values, not our verified price history.
Offer and eligibility may change at checkout. Choose by function and whole-life cost before judging the discount.
Sources & verification
Facts below are taken from the linked sources; product information may change. Last editorial check: 13 November 2026. No hands-on product testing was performed.