WaterBoost ATX-300 Whole House Mains Pressure Booster

What is the WaterBoost ATX-300?

The WaterBoost ATX-300 is the second largest model in the ATX integrated accumulator booster range. It connects directly to your incoming cold water mains supply, combining a 300-litre sealed accumulator vessel with a variable speed pump in a single compact unit — automatically boosting both pressure and flow throughout the property the moment a tap or shower is opened. No break tank, no overflow arrangement, and just two water connections required.

The 300-litre vessel provides 180 litres of useable working capacity, enabling the ATX-300 to sustain a boosted flow of 27 l/min at 3.2 bar for up to 11 minutes — sufficient for two or more showers running simultaneously — before the vessel recharges automatically. Peak burst flow at the moment of demand is up to 45 l/min. Once the stored volume is exhausted, the system continues to deliver a boosted 12 l/min at 3 bar continuously until demand ceases and the vessel refills.

Energy efficiency — only boosts what your mains can’t deliver

The variable speed pump continuously measures incoming mains pressure and adjusts its output to produce only the shortfall. If your mains delivers 1 bar and your target is 3 bar, the pump generates 2 bar. If your mains delivers 2 bar, the pump generates 1 bar. No wasted energy, no fixed worst-case output.

This is a fundamental advantage over water storage tank boosters, which run at the same full output regardless of what the mains already provides. Running costs with the ATX-300 reflect exactly what is needed — nothing more. Properties where mains pressure improves at off-peak times automatically benefit from lower running costs with no manual adjustment required.

Sealed system — zero air contact with your water

The ATX-300 operates as a fully closed pressurised circuit from mains inlet to outlet. The accumulator vessel is sealed and pressurised — there is no open water surface, no air gap, and no point at which atmospheric air contacts the stored water. This is a fundamentally different design to an open storage tank system, with important advantages for water quality and safety.

The pump body is constructed from WRAS-approved materials throughout, confirming suitability for contact with potable water. The complete system carries WRAS approval.

Zero maintenance — fit it and forget it

The ATX-300 is a completely maintenance-free system. There are no consumable parts, no filters to replace, no annual service requirements and no engineer visits needed. The sealed design removes the hygiene maintenance obligations of open storage, and the built-in anti-seize exercise function and dry run protection mean the system manages its own long-term health automatically.

How it works — two-phase operation

The ATX-300 stores a ready supply of pressurised water in its 300-litre accumulator vessel. When demand occurs, it delivers instant high-flow boosted water immediately, then continues at a sustained flow once the stored volume is used, before recharging automatically.

How it compares — WaterBoost ATX-300 vs Stuart Turner Stormboost 300

Both systems target the same market — 300-litre direct mains boosters for 2-bed homes upwards.

Technical specifications

Flow rates are dependent on incoming mains supply. Continuous flow of 12 l/min applies after stored volume is exhausted.

Frequently asked questions