Company lists · Data refreshed September 2026

Top 25 Water treatment plant contractors based in the United Kingdom

Name: Water treatment plant contractors based in the United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 19, 2026 211 companies tracked

RevenueBase identified 211 water treatment plant contractors headquartered in the United Kingdom as of September 2026 and tracks 4,383 professional contacts across them, including 2,062 with verified work emails. London is the largest hub.

This list covers water treatment plant contractors headquartered in the United Kingdom, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 19, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 19, 2026 86% judged on-target in blind review

211Companies

4,383Contacts tracked

2,062Verified emails

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The 25 largest water treatment plant contractors based in the United Kingdom

Ranked by team size

Top 25 of 211 water treatment plant contractors based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to water treatment plant contractors: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	MWH Treatment	Strong evidence	Stockport, United KingdomHQ checked Sep 19, 2026	1,001-5,000	879 contacts →
	Strong evidence “MWH Treatment is a leading Design and Build non-infrastructure solution provider in the UK water sector, with a water sector heritage dating back to 1820.” Source: RevenueBase Database · checked Sep 19, 2026
2	RSE	Partial evidence	Inverness Highlands, United KingdomHQ checked Sep 19, 2026	501-1,000	498 contacts →
	Partial evidence “RSE is a trusted clean water technology company, developing market leading products and solutions for purifying drinking water, recycling wastewater and cleaning water in…” Source: RevenueBase Database · checked Sep 19, 2026
3	Biwater	Partial evidence	Surrey, United KingdomHQ checked Sep 19, 2026	501-1,000	178 contacts →
	Partial evidence “Biwater is a world leader in treated water, providing large-scale water and wastewater solutions for clients across the world.” Source: RevenueBase Database · checked Sep 19, 2026
4	Severn Trent Services	Indirect evidence	Coventry, United KingdomHQ checked Sep 19, 2026	1,001-5,000	137 contacts →
	Indirect evidence “Severn Trent Services offer a range of services to municipal and industrial clients, including the Ministry of Defence and the Coal Authority, for design, build and operation of…” Source: RevenueBase Database · checked Sep 19, 2026
5	Enpure	Strong evidence	Birmingham, United KingdomHQ checked Sep 19, 2026	51-200	113 contacts →
	Strong evidence “Enpure is a process engineering company specializing in water, wastewater and sludge treatment as well as waste-to-energy solutions with a global presence.” Source: RevenueBase Database · checked Sep 19, 2026
6	Feedwater Limited	Strong evidence	Moreton, United KingdomHQ checked Sep 19, 2026	51-200	79 contacts →
	Strong evidence “Feedwater Ltd is a UK Water Treatment Company, established in 1976 specifically to supply products and services for the treatment of water for steam boilers, cooling towers…” Source: RevenueBase Database · checked Sep 19, 2026
7	Nijhuis Saur Industries UK And Ireland	Partial evidence	United Kingdom & Ireland, United KingdomHQ checked Sep 19, 2026	201-500	76 contacts →
	Partial evidence “At Nijhuis Saur Industries UK & Ireland our aim is to help our customers realise the value of their water and wastewater.” Source: RevenueBase Database · checked Sep 19, 2026
8	Envirogen Group	Strong evidence	Alfreton, United KingdomHQ checked Sep 19, 2026	201-500	75 contacts →
	Strong evidence “Envirogen Group is a global leader in industrial water treatment and process filtration solutions.” Source: RevenueBase Database · checked Sep 19, 2026
9	Siltbuster LTD	Strong evidence	Monmouth, United KingdomHQ checked Sep 19, 2026	51-200	75 contacts →
	Strong evidence “At Siltbuster Ltd, we operate the UK’s largest rental fleet of water treatment systems, setting the industry benchmark for rapid, reliable, and cost-effective solutions.” Source: RevenueBase Database · checked Sep 19, 2026
10	Richard Alan	Indirect evidence	Dewsbury, United KingdomHQ checked Sep 19, 2026	51-200	74 contacts →
	Indirect evidence “Established in 1970, the West Yorkshire-based Richard Alan Group is a portfolio of businesses providing high-quality Engineering Design, Manufacture, Installation and Servicing to…” Source: RevenueBase Database · checked Sep 19, 2026
11	Jacopa Limited	Indirect evidence	West Bromwich, United KingdomHQ checked Sep 19, 2026	51-200	73 contacts →
	Indirect evidence “Many of the best known, most respected and reliable brand names in the wastewater industry are part of Jacopa's heritage.” Source: RevenueBase Database · checked Sep 19, 2026
12	GEL Engineering	Indirect evidence	Enfield, United KingdomHQ checked Sep 19, 2026	51-200	70 contacts →
	Indirect evidence “Welcome to Gel Engineering.” Source: RevenueBase Database · checked Sep 19, 2026
13	ESD Joint Venture	Partial evidence	Stepps, United KingdomHQ checked Sep 19, 2026	201-500	58 contacts →
	Partial evidence “How we manage water and wastewater systems now will be critical for our communities and ecosystems for many generations to come.” Source: RevenueBase Database · checked Sep 19, 2026
14	Hydrotec Water Treatment Specialists	Strong evidence	High Wycombe, United KingdomHQ checked Sep 19, 2026	51-200	50 contacts →
	Strong evidence “Hydrotec is the UK’s leading company in the design and manufacture of water treatment products for the building services industry.” Source: RevenueBase Database · checked Sep 19, 2026
15	Colloide	Partial evidence	Tyrone, United KingdomHQ checked Sep 19, 2026	51-200	46 contacts →
	Partial evidence “Colloide Engineering Systems are a process engineering company, delivering tailored solutions for clients across many industries including Water and Wastewater, Food & Drink…” Source: RevenueBase Database · checked Sep 19, 2026
16	Hydro International UK Wastewater Services	Partial evidence	Portland, United KingdomHQ checked Sep 19, 2026	201-500	45 contacts →
	Partial evidence “Hydro International, a CRH Company, provides advanced products, services and expertise to help municipal, industrial and construction customers to improve their water management…” Source: RevenueBase Database · checked Sep 19, 2026
17	Panton Mcleod	Strong evidence	Selkirk, United KingdomHQ checked Sep 19, 2026	11-50	35 contacts →
	Strong evidence “Our teams are dedicated to supporting our clients to protect, maintain and improve water quality within treatment and distribution systems.” Source: RevenueBase Database · checked Sep 19, 2026
18	Marsh Industries LTD	Strong evidence	Northamptonshire, United KingdomHQ checked Sep 19, 2026	51-200	33 contacts →
	Strong evidence “Marsh Industries delivers world-class water/wastewater treatment products and solutions to the domestic, commercial, agricultural and leisure sectors from its UK manufacturing…” Source: RevenueBase Database · checked Sep 19, 2026
19	Wcsee Wastewater Marlowe Environmental Services	Indirect evidence	Gloucester, United KingdomHQ checked Sep 19, 2026	11-50	32 contacts →
	Indirect evidence “At WCSEE we collaborate closely with our clients to design and deliver reliable, robust, and future-proofed wastewater systems tailored to site specific requirements.” Source: RevenueBase Database · checked Sep 19, 2026
20	Arvia Technology	Strong evidence	Runcorn, United KingdomHQ checked Sep 19, 2026	11-50	32 contacts →
	Strong evidence “Tertiary water treatment specialist.” Source: RevenueBase Database · checked Sep 19, 2026
21	Watertight Management	Partial evidence	Bromsgrove, United KingdomHQ checked Sep 19, 2026	51-200	31 contacts →
	Partial evidence “Watertight Management has established itself as a leader in the provision of Clean and Waste water management services.” Source: RevenueBase Database · checked Sep 19, 2026
22	Rhames	Indirect evidence	Nottingham, United KingdomHQ checked Sep 19, 2026	51-200	29 contacts →
	Indirect evidence “rhames are innovators within the Manufacturing & Engineering Services sector specialising in Pharmaceutical, Petrochemical and Utilities industries with key representations within…” Source: RevenueBase Database · checked Sep 19, 2026
23	Lubron UK	Strong evidence	Colchester, United KingdomHQ checked Sep 19, 2026	51-200	26 contacts →
	Strong evidence “Lubron Water Technology UK is part of the European Market leading water treatment provider, Lubron Group, which has subsidiaries in the Netherlands, Germany and Belgium.” Source: RevenueBase Database · checked Sep 19, 2026
24	Retroflo	Strong evidence	Seaham, United KingdomHQ checked Sep 19, 2026	11-50	25 contacts →
	Strong evidence “Based in the North East of England, Retroflo Ltd are an Electrical and Mechanical contractor whose main activities are focused in the water industry.” Source: RevenueBase Database · checked Sep 19, 2026
25	Smoothflow Water Treatment & Commissioning	Strong evidence	Rickmansworth, United KingdomHQ checked Sep 19, 2026	51-200	23 contacts →
	Strong evidence “Smoothflow have been setting benchmark standards since our inception in 1992 and has grown into one of the most highly regarded providers of water treatment, commissioning &…” Source: RevenueBase Database · checked Sep 19, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: water treatment plant contractors. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names water treatment plant contractors.
Partial evidence: Its own public description names part of water treatment plant contractors, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name water treatment plant contractors. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 211 water treatment plant contractors based in the United Kingdom

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Water treatment plant contractors based in the United Kingdom at a glance

As of Sep 19, 2026

47.0%Verified-email coverage

20.8Average contacts per company

11-50Median size (employees)

3.3%Largest-city concentration · London

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

1,001-5,000

Email recency for this list is measured worldwide rather than for United Kingdom, so it is reported there. Company counts and contact totals on this page are exact for United Kingdom, over 211 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among water treatment plant contractors, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in the United Kingdom whose own description of what they do matches “water treatment plant contractors”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names water treatment plant contractors), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among water treatment plant contractors, and records with no verified work email. Companies headquartered outside United Kingdom are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 2,062 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 19, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names water treatment plant contractors, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many water treatment plant contractors are there based in the United Kingdom?

RevenueBase identified 211 water treatment plant contractors headquartered in the United Kingdom as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

MWH Treatment, headquartered in Stockport, tops this list with the largest team on record.

Which city has the most water treatment plant contractors?

London leads with 7 headquartered companies, followed by Coventry (4) and Manchester (4).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 2,062 verified decision-maker contacts tracked across these 211 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 19, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.