Why a house needs a water conditioner
In hard water areas, limescale builds up inside hot water systems, tapware and anything with a heating element — reducing flow, clogging aerators and shortening the life of the gear you've just installed. The RBM ActivFlo water conditioner range tackles that mechanically: no chemicals, no electricity, no magnets, and nothing to maintain once it's fitted to the main supply line. It's WaterMark certified across the range and carries a 15 year manufacturer's guarantee, with an expected working life beyond 20 years.
Threaded or compression — match the existing pipework
ActivFlo comes in two residential connection types, and the choice isn't about performance, it's about what you're connecting to. The Residential Threaded model uses a BSP male fitting, while the Residential Compression model is supplied with copper olives and brass nuts for a straight compression joint onto copper pipe. If the main is already threaded (a meter set, an isolation valve outlet), go threaded; if you're breaking into copper pipe mid-run, compression saves a transition fitting.
Sizing it to the house
Both residential lines are sized the same way, by bedroom count and the flow that implies: 15mm suits a 1–2 bedroom property (1–2 people) up to 33 L/min, 20mm suits a 3–4 bedroom property (3–5 people) up to 66.7 L/min, and 25mm suits a 5–6 bedroom property (6–7 people) up to 102 L/min. Undersizing creates a pressure drop across the unit at peak demand (multiple showers, a bath filling and the dishwasher running); oversizing just costs more for no benefit. Match it to the property, not the pipe you happen to be connecting to.
Stepping up to commercial
Apartment buildings, commercial kitchens and irrigation feeds outgrow the residential range fast. The Commercial BSP-Threaded line runs 32mm to 65mm in a 550mm-long, 316 stainless steel body, and the Commercial Flanged line covers 80mm and 100mm in an 850mm body (125mm and 150mm are POA). Both share the same operating envelope as the residential units — max 1,600 kPa static pressure, 99°C maximum temperature — scaled up in body size rather than redesigned, which is why the install footprint jumps noticeably once you move past 65mm.
The nano unit isn't just for espresso machines
The ActivFlo Nano is a different scale problem: a compact 3/8" BSP-M, 100mm-long unit rated for 1–11 L/min, built to sit inline on a single piece of commercial equipment rather than a whole building. It's specified for commercial coffee and espresso machines, but the same low-flow protection applies to commercial laundry equipment — anywhere scale damages a specific machine faster than it damages the building's pipework generally.
Frequently Asked Questions
Does the ActivFlo need power, chemicals or a magnet to work?
No — it's a mechanical, fit-and-forget device. There's no electrical connection, no cartridge or chemical to replenish, and no magnet; the only maintenance is making sure it stays insulated if it's installed somewhere that drops below 0°C.
What size ActivFlo does a standard 4-bedroom house need?
The 20mm residential unit, rated to 66.7 L/min, which covers a 3–4 bedroom property with 3–5 occupants. Go to 25mm for a larger 5–6 bedroom household.
Should I choose threaded or compression?
Match it to what you're connecting to. Threaded suits a BSP-threaded outlet (a meter set or isolation valve); compression is supplied with copper olives and brass nuts for jointing straight onto copper pipe.
Is the Nano unit only rated for espresso machines?
No — it's specified for both commercial coffee/espresso machines and commercial laundry equipment, anywhere a single low-flow appliance needs scale protection rather than the whole building.