Mono, pillar and mixer: matching the tap to the basin
A mono tap has a single body with one lever or handle controlling both hot and cold through internal mixing, and needs a single tap hole. It is the standard choice on modern basins with one pre-drilled hole.
Pillar taps are separate hot and cold taps, each needing its own tap hole, typically found on older or traditional-style basins and baths. Replacing pillar taps with a mono tap on the same basin is not possible unless the basin has (or can be adapted to have) a single central hole.
Bath and shower mixer taps combine hot and cold with a diverter to a shower handset, and need enough deck space or wall clearance for the body and any exposed pipework. Wall-mounted versions need pipework repositioned within the wall before the tap face can be fitted.
Always check the number and spacing of tap holes on the basin or bath before ordering. It is the single most common reason a tap arrives on site and cannot be fitted as planned.
How the connection actually works
Most modern taps connect via flexible tails, braided flexible hoses running from the tap's threaded tail to the isolation valve or supply pipe. They come in standard lengths (300mm and 500mm are common) and the right length avoids a stretched or kinked connection under the basin.
An isolation valve (also called a service valve) sits between the supply pipe and the flexi tail, letting you shut off that one tap without draining the whole house. Fitting new isolation valves whenever we change a tap is standard practice for us, since old valves seize and a seized valve turns a five-minute future repair into a full water shut-off.
On older pipework with compression or soldered fittings straight to the tap, converting to flexible tails and an isolation valve is a small extra job that makes any future tap change far quicker.
Basin and bath taps are secured from below with a back nut, tightened enough to seal against the tap's washer but not so much that it cracks a ceramic basin, which is a genuine risk with heavy-handed tightening on some basin materials.
Water pressure and system compatibility
Combi boiler systems typically deliver good, consistent mains pressure to every tap, which suits the vast majority of taps on the market including most mixer taps without extra consideration.
Gravity-fed systems, common in older houses with a loft cold water tank, deliver lower pressure. Some mixer taps, particularly ones designed for combi or unvented systems, will run poorly or unevenly on gravity pressure, so checking the manufacturer's minimum pressure requirement against your system type matters before buying.
Unvented cylinder systems generally give strong, balanced pressure similar to a combi, and suit the same wide range of taps.
If you are not sure what system your home has, this is exactly the sort of thing we check at survey rather than something you need to work out yourself before choosing a tap.
What it costs to replace
Prices below cover removal of the old tap, fitting a new one with new flexi tails and isolation valves, and testing. They assume standard access under the basin or bath; boxed-in or very tight pipework can add time.
| Job | Typical fitted price |
|---|---|
| Basin mono tap, like for like | £70-£130 |
| Pair of pillar taps | £100-£180 |
| Bath filler or bath/shower mixer | £110-£200 |
| Kitchen mono mixer (including flexible tails) | £90-£160 |
| New isolation valves per tap (if not already fitted) | £20-£40 extra each |
Small things worth checking before you buy
Deck thickness. Some basins and worktops are thicker than a tap's standard shank length allows, which needs an extension kit agreed before fitting day.
Reach and height, especially over a deep basin or a butler sink, where a standard-reach tap can splash rather than land in the bowl.
Finish matching across the room. Chrome, brushed nickel and matt black all come from different suppliers with slightly different tones, so buying the tap, waste and any accessories from the same range avoids a mismatch you will notice every day.
This is light plumbing work; we do not carry out any gas or electrical work as part of a tap change, and any wider pipework or boiler-related issue found on the day gets flagged rather than worked around.
Where to read next
Questions we get asked most
Can I fit a mono tap where I currently have two pillar taps?
Only if the basin has, or can have, a single central tap hole. Most basins drilled for pillar taps cannot simply take a mono tap without changing the basin itself.
Do you always replace the isolation valves?
We recommend it whenever the existing ones look old or feel stiff to turn. A seized valve means the whole house needs shutting off for the next repair, which is a false saving.
Will any mixer tap work with my water tank in the loft?
Not necessarily. Gravity-fed systems run at lower pressure, and some mixer taps need a stated minimum pressure to perform properly, so we check this against the tap's specification before fitting.
How long does a tap replacement take?
A straightforward like-for-like swap with clear access is usually 45 minutes to an hour per tap. Tighter access or old seized pipework can extend this.
Can I supply my own tap for you to fit?
Yes. We just ask that you check the tap hole configuration and shank length against your basin or bath before ordering, since mismatches are the most common cause of a delayed fitting day.