---
title: "Flexible hoses and flexi tap connectors: the EPDM Legionella risk HSG274 warns about"
source_url: https://legionella.io/articles/flexible-hoses-flexi-connectors-legionella/
canonical_url: https://legionella.io/articles/flexible-hoses-flexi-connectors-legionella/
pillar: "Legionella Risk Assessment"
summary: "Why EPDM-lined flexi tap connectors and braided hoses get flagged for Legionella, how to spot the high-risk ones, and what compliant replacement looks like."
primary_keyword: "flexible hoses Legionella"
date_published: 2026-06-16
date_reviewed: 2026-06-26
author: "Legionella.io editorial team (REMOTE TECH LTD)"
reviewed_against: "HSE L8 and HSG274 guidance"
region: "United Kingdom"
license: "(c) REMOTE TECH LTD. Quote freely with attribution and a link to source_url."
---

# Flexible hoses and flexi tap connectors: the EPDM Legionella risk HSG274 warns about

Flexible connectors keep landing on risk assessments because the rubber lining inside many of them, usually EPDM, leaches carbon and nutrients that feed biofilm, while the hose itself sits warm, stagnant and hidden under a basin. Not every flexi is a hazard. But the type, the location and the age decide whether it is a minor note or something to cut out this quarter.

That is the gap a recurring flag leaves you with. The assessor writes "flexible hoses present, recommend removal or replacement," and then you have to decide which of the forty under-sink connectors across a building actually matter, and what to fit in their place.

## What the hose is doing wrong

A braided flexible connector is the short, woven-metal-sleeved hose that joins a rigid pipe tail to a tap, mixer or appliance. The braid is stainless or aluminium and is structural only. The water touches the inner tube, and on cheaper or older fittings that tube is an elastomer, commonly EPDM (ethylene propylene diene monomer).

Two things make that liner a problem for water hygiene.

First, the material itself. Non-metallic wetted surfaces can release organic compounds into the water in contact with them, and those compounds are food. A surface that gives up carbon supports biofilm, and biofilm is where Legionella and other organisms shelter, feed and amplify. HSG274 is explicit that materials in contact with water should not support microbial growth, and points back to the Water Supply (Water Fittings) Regulations for what counts as acceptable [1].

Second, the geometry and the spot it lives in. A flexi connector has a convoluted, rough internal bore with far more surface area than the smooth copper it replaced. It is usually fitted in a warm cupboard under a basin, downstream of a tap that gets used twice a day, so the water inside it sits in the growth range for hours. You have built a small, warm, nutrient-rich, low-flow pocket. It is the same trap you chase elsewhere as a [Dead legs and blind ends: how to find, assess and remove them](https://legionella.io/articles/dead-legs-and-blind-ends-how-to-find-assess-and-remove-them/), except this one is mass-produced and fitted by the thousand.

## EPDM is not banned, uncontrolled EPDM is the issue

It pays to be precise here, because "rip out every flexible hose" is not what the guidance says and is rarely affordable.

The control point is material approval. Non-metallic products used in contact with wholesome water should meet BS 6920, the test standard behind WRAS approval, and the fitting should be listed in the Water Fittings and Materials Directory. A WRAS approved flexible hose has been assessed for its effect on water quality, including whether it encourages microbial growth. An unmarked, unbranded builder's-merchant special has not, and you cannot assume it is inert.

So the real division is less "EPDM versus not" and more "approved and traceable versus unknown and ageing." Newer connectors increasingly use lower-leaching liners precisely because of this history, which is why the markings on the fitting matter as much as the material name. The [The Water Supply (Water Fittings) Regulations, WRAS and Legionella risk](https://legionella.io/articles/the-water-supply-water-fittings-regulations-wras-and-legionella-risk/) sit underneath this whole decision.

## The healthcare position is stricter

In NHS and augmented-care settings the bar is higher. A Department of Health Estates and Facilities Alert, DH(2010)03, warned about flexible water supply hoses after EPDM-lined connectors were linked to microbial growth, and drove their removal from high-risk clinical water systems. If you manage healthcare, dental or care premises, treat a flexible hose on an outlet used by vulnerable people as a presumption to remove, not a maybe, and let the water safety group confirm the call.

## Find them, judge them, decide

Work outlet by outlet. You are not just counting hoses; you are deciding which to leave, which to schedule, and which to change now. Take this list round the building with a phone camera.

**Locate**

- Open every basin, sink, WC, bidet, appliance and TMV cupboard. Flexis hide behind panels and kickboards.
- Note the connector type: braided flexible connector, flexi tap connector (the kind with an integral tap tail), or appliance fill hose.
- Photograph the markings on each one. Look for a WRAS approval mark, a brand and a date or batch code.

**Assess**

- Liner material if stated (EPDM, PE-X, silicone) and whether the fitting is approved and listed.
- Length and slack. A long, looped hose holds far more standing water than a short, taut one.
- Location temperature: warm plant cupboard versus a cold, ventilated void.
- Age and condition: discolouration, kinking, weeping, white scale or slime at the connection.
- The outlet it serves: how often it is used, and who uses it (an augmented-care wash-hand basin is not a cleaner's tap).

**Decide and rank**

- High priority: long, unmarked or old hoses on little-used or vulnerable-user outlets, and any in warm spaces.
- Medium: approved hoses in warm locations or on infrequent outlets. Flush, monitor and plan replacement.
- Low: short, approved, traceable connectors on well-used cold outlets in cool voids.

Record each decision in your asset register and written scheme of control, so the next assessor sees the reasoning and not just the verdict [2].

## What "replace with" actually means

Three honest options, in order of preference where it is practical.

**Eliminate.** The cleanest fix is a rigid copper or approved plastic pipe tail with a compression or push-fit connection and no flexible section at all. On a fixed tap that never moves, you rarely need a hose in the first place.

**Substitute.** Where a flexible section is genuinely needed, for a pull-out spray, a movable appliance or awkward alignment, fit a WRAS approved connector with a low-leaching liner, kept as short as the installation allows.

**Manage.** For the ones you cannot reach this month, fold them into the routine: flush the served outlet, keep the cupboard as cool as you can, and re-inspect at your scheme's interval.

On timing, resist the urge to write "replace every X years" as a blanket rule. Manufacturers give a service life for their product, and your risk assessment sets the priority and frequency for your building [3]. A short approved hose on a busy tap and a baggy unmarked one behind a rarely used cleaner's sink do not deserve the same clock.

## Where this sits next to your other outlet work

Flexible hoses rarely fail in isolation. The same cupboards hide the flow-straightener problems covered in [Spray taps and tap aerators: the Legionella risk hiding in your flow straighteners](https://legionella.io/articles/spray-taps-aerators-legionella/), and the shower hose in a guest bathroom is its own version of this story, a long, ribbed tube that drains and refills with every use, which is why [Showerhead cleaning and descaling schedules](https://legionella.io/articles/showerhead-cleaning-and-descaling-schedules/) treats the hose and not just the head. Tackle them as one outlet, not three separate line items.

## A note on scope

This is general guidance, not a design specification or a legal opinion for your site. Material suitability, removal decisions and replacement frequencies have to be set by a competent person through a site-specific risk assessment, working from the actual fittings in front of them and the people the water serves. Where healthcare or augmented care is involved, the specialist water safety group owns the decision.

## FAQ

### Are all flexible hoses a Legionella risk?

No. The risk comes from non-metallic liners that can support microbial growth, combined with stagnation and warmth. A short, WRAS approved connector on a frequently used cold outlet in a cool void is low risk. A long, unmarked, ageing hose in a warm cupboard on a little-used tap is the one to act on.

### What does EPDM stand for, and why does it matter?

EPDM is ethylene propylene diene monomer, a synthetic rubber widely used as the inner liner of flexible connectors. Some EPDM formulations release nutrients that encourage biofilm, which is why uncontrolled, unapproved EPDM-lined hoses get flagged. Approval to BS 6920 and WRAS is the assurance that the liner has been tested for that effect.

### How do I know if a flexi connector is WRAS approved?

Look for a WRAS approval mark and the maker's name on the fitting or its packaging, and check the Water Fittings and Materials Directory. No marking, no brand and no paper trail means you cannot assume it meets the Water Fittings Regulations, so treat it as suspect until proven otherwise.

### How often should flexible hoses be replaced?

There is no single legal interval. Follow the manufacturer's stated service life and let your risk assessment set the priority. Condition, location, liner type and the outlet's users matter more than age on its own.

## Your next step

Pull your last risk assessment and find every line that reads "flexible hose." Take the checklist above to the ten highest-risk of them this week, the long, unmarked, warm-cupboard ones on outlets used by the fewest or the most vulnerable people, and book those for elimination or approved replacement. Log the decision against each asset, so the flag stops reappearing unanswered next year.

## Sources

[1] HSE, "Legionnaires' disease: Technical guidance (HSG274)". https://www.hse.gov.uk/pubns/books/hsg274.htm
[2] HSE, "Legionnaires' disease. The control of legionella bacteria in water systems - Approved Code of Practice and guidance (L8)". https://www.hse.gov.uk/pubns/books/l8.htm
[3] BSI, "BS 8580-1:2019 - Risk assessments for Legionella control. Code of practice". https://knowledge.bsigroup.com/products/water-quality-risk-assessments-for-legionella-control-code-of-practice-1