Water Filtration near you

People often assume a domestic filter carries some form of official approval. It does not, and the reason is worth knowing. Regulation 31 of the Water Supply (Water Quality) Regulations 2016 is the approval regime for substances and products used in connection with the supply of drinking water, and the Drinking Water Inspectorate administers it. But the Inspectorate states that the only products considered for approval under regulation 31 are those sold to water undertakers in the United Kingdom for use with water intended for human consumption.

Products used in customers' premises and in public buildings fall outside regulation 31 altogether. The Inspectorate's approval covers treatment chemicals, treatment process products such as adsorbents, ion exchange resins and membranes, pipes and associated components, coatings and repair materials — all of them going into the network and the treatment works, not into your kitchen cupboard. It also confirms that approval under regulation 31 is not required for private water supply products.

What does apply to a filter you install at home is a different regime entirely: the water fittings rules, which govern what may be connected to a supply and how. That is why the Inspectorate's consumer advice is to use a qualified plumber to install a device and to check in advance with your water company that the device meets the water fittings regulations. The regulation 5 notification list and the fluid category grading behind those rules are set out in the plumbing and handyman guides on this site; the point here is simply that nobody in government has approved the filter itself.

Start with what filtration cannot change. On a mains supply, hardness is a matter of the local geology and a carbon filter does not address it. Discolouration arising in the water company's network is the company's problem to investigate, not yours to filter out. And a filter cannot make an unwholesome supply wholesome by itself — the Inspectorate advises whole supply treatment in preference to point of use wherever possible, and without exception where a private water supply is being used as part of a commercial or public activity.

Then the risk that comes with the device. The DWI's advice is to always follow the manufacturer's guidance about cleaning and maintenance and the frequency of changing cartridges, because failure to do so will cause a build-up of deposits, create a breeding ground for bacteria and cause leaching of removed material back into the drinking water. A filter that has been in place since the kitchen was fitted is not a neutral object; it is a warm, wet, organic-rich environment that nobody has looked at.

The Inspectorate also notes a small thing that causes a large amount of alarm: if you see small black particles in your water after treatment through an activated carbon filter, those particles are unlikely to have originated from your tap water and will instead be particles of activated carbon from the filter itself. Worth knowing before anyone photographs a glass of water and sends it to the water company.

On a mains supply, filtration is optional refinement. The water arriving at your boundary has already been through a treatment works and a regulated monitoring regime, and the DWI is explicit that there is no need to install additional treatment within the home as a health protection measure. Where a localised problem does produce particulate matter or colour in tap water because of a fault with pipes and fittings for which the building owner is responsible, the Inspectorate accepts that a suitable filter may improve the aesthetic water quality as a temporary measure — note the words temporary and aesthetic.

On a private supply drawn from a borehole, well, spring or watercourse, filtration is a stage in an engineered treatment system rather than a consumer product, and choosing it from a catalogue is how private supplies fail. The Inspectorate's position is that treatment should be selected on a case-by-case risk basis, taking account of the vulnerability of those likely to use it, and that installing a point of use device must not compromise human health at any point on a supply where the water is used for a domestic purpose. The regulatory duties that sit around a private supply, and the local authority's role in them, are covered in the well services guide on this site.

The practical rule is that a filter is a reasonable thing to buy for a mains supply when you know what you are trying to improve, and never the first thing to buy for a private supply — there, the risk assessment and the sampling come first, and the treatment is designed from what they find.

The install is usually the smaller half of the cost over any length of time. What moves the initial quotation is whether the unit is point of use under a sink or whole-house on the rising main, whether a separate filtered tap is being added and whether the worktop needs drilling, how accessible the rising main is and whether isolation valves already exist, whether a waste connection is required, and whether any notification to the water undertaker is needed. What moves the running cost is cartridge price and change frequency, which varies enormously between systems and is the figure to ask about before you choose one. A system with cheap cartridges changed twice a year can easily outrun a dearer one changed annually.

LokalMatch handles the introduction only. Describe what you want to improve about your water once, say whether you are on a mains or a private supply, add your postcode, and installers covering your area will get in touch. Homeowners pay nothing to use it and pros pay for the requests they receive. LokalMatch neither supplies nor fits filtration equipment, has no influence over what anyone charges, and does not vet, rank or recommend the businesses that respond — so asking each of them what the cartridges cost and how often they need changing is a question for you.