WaterBoost Compact
The WaterBoost Compact is a low-mains booster pump that connects inline, directly to your incoming supply — delivering increased water pressure of up to 4.5 bar throughout the property. No storage tank, no break tank: a simple, space-saving way to fix weak mains pressure.
It works automatically — sensing demand and increasing pressure the moment your mains falls below the pump’s pre-set value, then settling back when it’s no longer needed. Compact, quiet and easy to install, it’s ideal for flats and smaller homes where pressure is poor and space is limited.
Why choose WaterBoost Compact?
Key specifications
| Type | Inline direct-mains booster pump |
| Max pressure | Up to 4.5 bar |
| Max flow | Up to 12 l/min (the maximum for a direct-mains booster under UK Water Regulations) |
| Operation | Automatic — activates when mains pressure falls below the pre-set value |
| Connection | Inline, directly onto the incoming mains |
| Tank | None required |
| Best for | Flats, apartments and 1–2 bathroom homes with low mains pressure |
Direct-mains boosters are limited to 12 l/min under UK Water Supply (Water Fittings) Regulations. For higher flow across multiple bathrooms, a tank-and-pump system is required.
For a simple, compact and automatic fix to low mains pressure — with no tank and minimal installation — the WaterBoost Compact is the easy answer. Choose your model below.
7 products
The WaterBoost WB-Compact 3.0 is a compact variable speed inline mains pressure booster that connects directly to the incoming mains supply — no tank, no…
The WaterBoost WB-Compact 4.5 (ACM Series) is a compact variable speed inline mains pressure booster — designed to boost your incoming mains supply to up…
The WaterBoost WB-Compact 4.5 ACF1 is a compact floor-mounted variable speed pump designed to charge external accumulator vessels to up to 4.5 bar. If your…
WB-Compact 4.5 ACW1 – Digital Accumulator Booster Pump (Wall Mounted) The WB-Compact 4.5 ACW1 is a digitally controlled, wall-mounted accumulator booster pump designed to deliver…
WaterBoost ACM connection kit Pump to pipework connection kit for easy instaltation. includes – 2 x 600mm 1″ braided hose 2 x 22mm x 1″…
The WaterBoost ACM wall bracket is a fitting kit designed to mount the ACM pump directly to a wall.
WaterBoost WB-Compact 3.0 Wall Dock Designed for effortless installation, the WaterBoost WB-Compact 3.0 Wall Dock provides a clean and professional solution for connecting your booster…
Frequently Asked Questions
Quick answers to common questions about the WaterBoost Compact. For technical specifications, see the product details above; for sizing or installation advice, contact our team. If you have any other questions, we're happy to help.
What is a mains pressure boosting system?
A mains pressure boosting system increases the pressure and flow of water from the incoming mains supply into a property. It typically combines a pump and a storage or expansion tank, drawing water from the mains and delivering it to taps, showers and appliances at a stronger, more consistent pressure. They are used where the incoming mains is too weak to serve modern outlets reliably.
When do I need a mains booster pump?
You normally need a mains booster if static mains pressure is below 1.5 to 2 bar, if showers run weakly when other taps are open, or if combi boilers struggle to deliver hot water. Anglian Pumping recommends checking static pressure at the stop tap before specifying a system, then choosing a model rated for the number of bathrooms and outlets in the property.
What size mains booster do I need for my home?
Sizing depends on the number of bathrooms, the type of fittings and the static mains pressure. As a guide, a 1 to 2 bathroom property with combi boiler or single shower often needs 1.6 to 3 bar boost. A 2 to 3 bathroom property typically needs 3 to 4.5 bar with an integral break tank. Larger homes need a tank-and-pump system such as the DAB Esybox with Esytank or a Powertank set.
What is an accumulator tank?
An accumulator tank is a pressurised vessel that connects directly to the mains supply and stores water under pressure. When a tap or shower opens, water discharges immediately from the vessel at full mains pressure rather than drawing only from the street main. This delivers stronger, more consistent flow at peak times. Accumulators have no pump and no moving parts so they are maintenance free and silent.
When should I use an accumulator instead of a pump?
An accumulator is the right solution when static mains pressure is adequate – above 2 bar – but flow is poor or drops during peak demand. It boosts available flow without adding a pump, energy use or noise. If static pressure is below 2 bar, a booster pump is needed instead, or an accumulator combined with a charge pump such as the WaterBoost ACF1.
What size accumulator do I need?
Accumulators are typically sized on a 60 per cent usable rule – a 300 litre vessel delivers around 180 litres of boosted water per cycle. As a guide, a 2 to 3 bedroom home suits a 300 litre vessel such as the GWS GCB-300LV. Larger 4 to 5 bedroom homes or properties with multiple bathrooms typically need 450 to 600 litres. Vertical models save floor space, horizontal models suit lofts and roof spaces.