Guide

Fitting an under-sink water filter without drilling

You can sometimes fit an under-sink filter without drilling a new hole in the sink or worktop, but only with some set-ups, and “no drilling” is not the same as “no changes”. Budget for the filter, any tap or adaptors, and a fitting quote for your kitchen. The cost examples below separate hardware from labour.

Tap Sorted guide · Updated 16 October 2026

What “without drilling” means

It means no new hole in the sink or worktop for a tap. It does not mean no changes at all. The filter still has to connect to the cold supply, the pipework under the sink may need adapting, and the housing’s mounting screws may still go into the cupboard. Nor is it a guarantee that the work can be undone, and it does not remove the need to ask your landlord if you rent: see if you rent. If you want no plumbing at all, a refillable countertop filter or dispenser can avoid a plumbing connection.

Which set-ups avoid a new hole

Start with the question of where the filtered water will come out of, and what you already have.

1. Use your existing tap→A system that connects to the existing cold line and uses your tap, which the Waterdrop WD-10UA’s maker says it does. Check the threads, valves and flow against its manual first.
2. Use a spare tap hole→A dedicated tap can go in an existing spare hole if it fits that hole. Some kitchens swap a tap for a three-way tap in the same hole, but compatibility varies, so ask the maker and your installer.
3. You need a new hole→Drilling stone or composite worktops is a professional job, not a general DIY one. Ask an installer who works with your worktop.
4. Reverse osmosis→Under-sink RO needs a drain connection and sends wastewater to drain. Many models also need power; check the exact unit. See the reverse osmosis guide.

• 

  Existing tap

  The WD-10UA connects to the existing cold line and uses your tap.

• 

  Own tap in the box

  Aquaphor and UK Water Filters each include a tap, so you need a hole for it.

• 

  Tap bought separately

  Doulton’s Kingfisher comes without a tap; a pillar tap is £44.95 extra.

Product photos come from the makers’ own pages; credits are on the comparison.

Connecting to your existing tap

This is the route that avoids a tap hole. Whether it works for you is a compatibility question: the connection on your supply, the isolating valve, the pressure and the flow all have to suit the model. Waterdrop’s web specifications and photographed label give different pressure limits. Confirm the permitted pressure in the instructions supplied with your exact UK kit before fitting. The maker’s page also decides how the filtered water reaches the tap, so read it before you buy. The housing itself still needs somewhere to mount, which may mean screws into the cupboard. The WD-10UA is a carbon filter, not reverse osmosis, so it has no RO drain; check the variant, because the maker sells a version for a dedicated tap too.

A dedicated tap in an existing hole

Many kitchens have a spare hole beside the main tap, from an old soap dispenser or a blanked fitting. A dedicated filter tap may fit it, but only if the hole size and the worktop thickness suit that tap. Systems whose tap is in the box, or sold separately, need that decision made before you order. The UK Water Filters kit, for example, will not work with an existing mixer tap. Our water filter taps page compares the taps and what each works with. Doulton strongly recommends a matched tap, separate or three-way, for its Kingfisher and notes a maximum filter flow of 1.9 litres a minute, so an existing tap is not a universal fit. The Aquaphor Crystal Solo needs a tap hole for its own tap.

When you need an installer

• A new hole in stone or composite. Drilling these worktops is specialist work, and a mistake can crack the surface.
• Plastic or unusual pipework. The UK Water Filters saddle connector is for copper pipe with about 5 cm exposed, and plastic pipe needs an adaptor or a plumber.
• A drain connection or power. Under-sink reverse osmosis needs a drain connection; powered models also need a suitable electrical supply.
• Anything you are unsure about. Connections to the cold supply have to meet the water fittings rules; see plumbing, approvals and quotes.

What installation costs

Fitting is quoted for your kitchen. The set-up, pipework, worktop and any extra parts affect the price, so compare written quotes for the same work. Start with the hardware prices below, then add your installer’s quote.

One published installer price, as a local example

The only installer price we have checked is from one firm, so it is an example and not a UK average, not a quote from us, and not a nationwide price. On 16 October 2026 RudiThePlumber’s cost page said installation “starts from £50” for straightforward single-stage systems, which it says includes the Waterdrop WD-10UA and WD-10UB, and that more complex systems including reverse osmosis typically start from £175. The firm covers Syston, Leicester and Leicestershire, and the page does not say whether VAT is included. The final price depends on the model, plumbing, drilling, waste, cupboard and power. We have no link or referral arrangement with this firm.

A starting price is not a total: we do not add it to the hardware prices to give you an installed cost. Ask for a written quote that says what it includes, including VAT.

Hardware prices are as checked on 16 October 2026 and change; the comparison has the dates and the cost over one, three and five years. When you ask for a quote, check that it says:

1. Whether the price is for labour only or includes parts such as adaptors, an isolating valve and pipe.
2. Whether a tap, if you need one, is included, and whether drilling is part of the job and for which worktop.
3. What is allowed for pipework changes, and for a drain or power if the model needs them.
4. Whether VAT, call-out and making good are in the figure.
5. Who is responsible if the fitting does not meet the water fittings rules.

Cartridges are the running cost after fitting. See the cartridge page for what each one fits and costs, the replacement guide for what they cost and how long they last, and the running-cost calculator for the five-year total.

How a fitting goes, in outline

This is an outline to help you talk to an installer, not instructions. The order is usually: turn off and isolate the supply, make the connection to the cold line, mount the housing, fit the tap or connect to the existing one, open the supply slowly, flush the new cartridge, and check every joint for leaks. The details, such as how far to turn a housing, how long to flush and how much water to run, are model-specific and are in the manual for your exact system. Follow the maker’s instructions first.

• Doulton Kingfisher manual
• Waterdrop WD-10UA product page and FAQ
• Aquaphor Crystal Solo product page
• UK Water Filters Anti-Scale kit page

For how the systems compare, see the under-sink comparison, and for the clearance you need to change cartridges later, measure the cupboard properly.

Common questions

Can you fit an under-sink water filter without drilling?

Sometimes. A system that connects to your existing cold line and tap, such as the Waterdrop WD-10UA by its maker’s description, needs no new tap hole, and a dedicated tap can go in a spare hole that already exists. A system whose tap needs a new hole, or an under-sink reverse osmosis unit may need an additional tap hole and a drain connection; powered models also need electricity. “No drilling” still allows changes to pipework and cupboard screws; see what it means.

How much does installing an under-sink water filter cost in the UK?

We have no verified national figure. The hardware prices above are real, and one Leicestershire installer publishes a starting price, but a written quote for your kitchen is the only reliable number. Use the quote checklist.

What next, once it is fitted?

Order the right replacement from the cartridge page, then keep to the schedule in the replacement and care guide.

General information, not installation advice. How we check.