Will a Fixed Shower Head Shower Filter Fit My Shower?

So you've got a fixed shower head, you want filtered water, and you're wondering whether a fixed shower head shower filter will actually fit before you go ahead and order. Smart thinking — and you've come to exactly the right place.

The short answer is: almost certainly yes. The vast majority of fixed shower heads in UK homes are completely compatible with a fixed shower head shower filter, and fitting one is a straightforward five-minute job that needs no special tools and no plumber.

But "almost certainly" is doing a little bit of work in that sentence. Because over the eighteen-plus years we've been selling shower filters here at PureShowers — the UK's #1 and original shower filter brand since 2008 — a small number of customers have hit a wall. Not because the filter is the wrong product, but because their shower head is one of a handful of less common types that need a little extra attention before a filter can go on.

This guide will help you figure out exactly which type of fixed shower head you have, tell you in plain English whether a filter will fit, and flag anything you need to sort out first — before you order, not after.

First Things First: What Kind of Shower Filter Are You Actually Looking For?

Before we get into compatibility, it's worth making sure we're all talking about the same type of filter — because there are a few different types of shower filter on the market and they work in quite different ways.

Handheld shower filters replace or attach to a handheld shower head on a hose. If you've got a handheld shower rather than a fixed one, this is the type you'd want — but since you're reading this article, that's probably not you.

Inline shower filters sit between your existing shower arm and your existing shower head. The water gets filtered before it reaches your head, but you keep your current shower head exactly as it is. A great option if you love your existing head and just want to bolt filtration onto it.

Fixed shower head filters — the type this article is about — replace your existing fixed shower head entirely. The filter is built right inside the shower head itself. You unscrew your old head, screw on the new one, and you're showering in filtered water. Simple as that.

PureShowers Fixed Shower Head — 5 Spray Settings, Multistage Filtration

Our own fixed shower head filter is a great example of this type. Five spray settings, multistage ionic and mineral filtration built right in, and it screws straight onto your existing shower arm just like any standard shower head.

One thing worth knowing right now: every fixed shower head shower filter on the market — every single one, without exception — is designed for a standard ½" BSP connection. No manufacturer makes a fixed shower head filter for any other connection size. Keep that in mind — it becomes relevant very shortly.

How to Check Your Shower Head

Right, this is the important bit. Take sixty seconds to do this check before you order anything, and you'll know exactly where you stand.

Over the years we've come across four distinct types of fixed shower head connection in UK homes. Here's how to identify which one you've got:

Type 1 — Standard ½" BSP (The One You Almost Certainly Have)

This is what the overwhelming majority of fixed shower heads in UK homes use. You've got a curved arm coming out of the wall, and your shower head screws onto the end of that arm via a threaded connection. Nice and simple.

How to spot it: Unscrew your shower head from the arm by turning it anti-clockwise. You'll see the end of the arm with spiral threads on the outside — like a big bolt. Grab a ruler or tape measure and check the outer diameter of those threads. If it's coming in at around 21–22mm, that's ½" BSP. You're golden.

A standard ½" BSP shower arm thread measures approximately 21–22mm across

Will a filter fit? Yes — completely. Unscrew your old head, screw on your new fixed shower head filter, done. That's genuinely all there is to it.

Type 2 — ¾" BSP (Older & Larger Dome Heads)

Less common than Type 1, but not exactly rare either. You tend to find these on older installations and on larger traditional dome-style shower heads. The arm looks very similar to Type 1 from the outside — it's still threaded — but the thread is noticeably chunkier.

How to spot it: Remove the shower head and measure the outer diameter of the threads on the arm. If it's coming in closer to 26–27mm rather than 21–22mm, you've got ¾" BSP.

You might also notice that when you hold a standard shower head filter up to the arm, it just rattles around rather than gripping — the filter's ½" inlet is simply too small for the ¾" thread.

A ¾" BSP shower arm thread measures approximately 26–27mm across — noticeably larger than standard

Will a filter fit? Not directly — but it's an easy fix. A ¾" to ½" BSP reducer adapter costs a few pounds from any plumbers merchant or online. Screw it onto the arm, screw the filter onto the adapter, job done. Five minutes, no drama.

Type 3 — Proprietary Thread Sizes & Fittings

Here's where it gets a little bit annoying — but only occasionally, and only with certain brands.

Most shower manufacturers play ball and use the global standard ½" BSP fitting. Everyone's happy, everything fits everything, life is good. But every now and then a manufacturer decides to go their own way and use a proprietary thread size — one that's completely unique to their own products. Which means the only thing that will fit onto their pipe is their own original shower head. Nothing else will engage, no matter what you try.

Not ideal for you as a consumer, because it basically means you're locked in. Can't swap in a new shower head, can't fit a filter head, can't do much without replacing the arm entirely.

In over eighteen years of selling shower filters, we've seen this happen very rarely. But the two brands where we've occasionally come across it are Aqualisa and Hansgrohe.

Quick disclaimer though: we're absolutely not saying either of these brands always does this. Plenty of Aqualisa and Hansgrohe showers use perfectly standard ½" BSP fittings and work fine with a shower filter. It's just that on the odd occasion a customer has scratched their head wondering why nothing fits, it's turned out to be one of those two. So if you've got either brand, just take the extra sixty seconds to measure yours before ordering — better to know now than when the parcel arrives.

Two examples of proprietary shower arms sent in by customers — thick, sculpted and architectural rather than a simple tube

Will a filter fit? Measure it first. If you're getting ~21–22mm at the thread, you're on standard ½" BSP and you're absolutely fine. If it's measuring noticeably different — drop us a message before you order and we'll help you figure it out.

Type 4 — Vandal-Resistant Through-Wall Heads

You'll know immediately if you've got one of these because there is no shower arm at all. The shower head mounts flat against the wall with bolts, and the water pipe comes directly through the wall into the back or bottom of the head. No arm, no exposed thread, no connection point to speak of.

These are most commonly found in gyms, sports centres, student accommodation, holiday parks and similar commercial settings — but they do occasionally turn up in domestic properties that were previously commercial, or where a builder used commercial fittings.

Will a filter fit? Honestly — no, not without plumbing work. There's simply no threaded connection to attach anything to. This one genuinely needs a plumber. Sorry.

Quick Reference

Not sure which type you've got? Here's the cheat sheet:

The Bottom Line

If you've done the check above and you've got a standard ½" BSP arm — which is the case for the vast majority of people reading this — you can order your fixed shower head shower filter right now with complete confidence. It will fit. It will screw straight on. Five minutes and you're done.

The edge cases in this article aren't here to put you off. They're here because after eighteen years of doing this, we'd rather help you get it right first time than have you scratching your head when the parcel arrives.

Got a question about your specific shower? Drop us a message — we genuinely love this stuff and we're always happy to help.