ClearwaterSewage Treatment Plants

Sizing is based on population equivalent — essentially the number of bedrooms or occupants the property is designed for, not how many people currently live there. The Clearwater BioAir CW Range covers systems from 6 up to 35 person equivalents, so a typical family home would use one of the smaller units while HMOs, holiday lets or small commercial sites need a larger model. If you're unsure, we can help you work out the right size from your occupancy and drainage layout.

Yes — installation must comply with Building Regulations (Part H), and if the treated effluent discharges to a watercourse rather than a soakaway, you'll usually need to register with the Environment Agency (or Natural Resources Wales in Wales) under the general binding rules. In some cases, such as discharge within a groundwater source protection zone, a full permit is required. Your installer can confirm which applies to your site before work starts.

A septic tank simply separates solids from liquid and relies on a drainage field to further treat the effluent before it returns to the ground. A sewage treatment plant, like the Clearwater BioAir range, actively aerates and biologically treats the wastewater on-site, producing a much cleaner effluent that can often be discharged directly to a watercourse. This makes treatment plants the better option where soil conditions are poor or a suitable drainage field isn't available.

Routine maintenance is minimal — an annual service by a qualified engineer to check the air blower, diffusers and internal components is generally all that's required, alongside periodic desludging (typically once a year, depending on usage). We stock a full range of Clearwater spare parts, including blowers and diffusers, so ongoing upkeep is straightforward and doesn't mean waiting on a specialist order.

It depends on the model and its trafficable rating — some Clearwater tanks can be specified with reinforced covers or upgraded to take vehicle loading, but this needs to be confirmed at the ordering stage rather than after installation. Access for desludging and servicing also needs to be considered in the siting, so it's worth planning tanker access before finalising the position. Speak to us before you order if the plant needs to sit under a drive or parking area.

An undersized plant will struggle to fully treat the volume of wastewater passing through it, leading to poor effluent quality, more frequent desludging and potential odour or compliance issues. This is why sizing should be based on the property's maximum likely occupancy (bedrooms) rather than current household size. If you're extending the property or adding occupants, it's worth checking your existing plant's capacity rather than assuming it will cope.