Company lists · Data refreshed September 2026
Top 25 Wastewater consulting firms based in the United Kingdom
RevenueBase identified 427 wastewater consulting firms headquartered in the United Kingdom as of September 2026 and tracks 9,094 professional contacts across them, including 3,533 with verified work emails. London is the largest hub.
This list covers wastewater consulting firms 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 29, 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.
The 25 largest wastewater consulting firms based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 1,255 contacts → | ||||
Indirect evidence “RSK Group is a global leader in the delivery of environmental and engineering solutions.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 2 | 879 contacts → | ||||
Indirect 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 29, 2026Thanks. The Data Team will review it. | |||||
| 3 | 842 contacts → | ||||
Indirect evidence “Together with our strategic partners, we can address everything from supporting vulnerable customers, water quality, asset performance and leak detection, to integrated planning…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 4 | 670 contacts → | ||||
Indirect evidence “Click the 'Follow' button and explore careers at Ricardo on our 'Jobs' and 'Life' tabs and at careers.ricardo.com.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 5 | 217 contacts → | ||||
Partial evidence “Supported by a network of specialist consulting engineers, environmentalists and our own collective experience, our philosophy is simple: to provide a qualitative economic and…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 6 | 178 contacts → | ||||
Indirect evidence “Originally established in 1977, OnSite is a South Staffordshire Group owned company that has grown through strategic acquisition and organic expansion to become one of the UK's…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 7 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 8 | 166 contacts → | ||||
Indirect 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 29, 2026Thanks. The Data Team will review it. | |||||
| 9 | 156 contacts → | ||||
Indirect evidence “Aqua Consultants provide tailored environmental consultancy to broaden your thinking, lead transformation, and achieve successful outcomes.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 10 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 11 | 136 contacts → | ||||
Indirect evidence “We’re envolve, specialist civil engineers.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 12 | 113 contacts → | ||||
Partial 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 29, 2026Thanks. The Data Team will review it. | |||||
| 13 | 112 contacts → | ||||
Indirect evidence “AWMS, part of Alumasc Group, is the first joined-up brand in integrated water management.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 14 | 101 contacts → | ||||
Indirect evidence “Isle’s vision is to be the leading catalyst in water industry transformation through exceptional business insight, technology, and innovative solutions.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 15 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 16 | 75 contacts → | ||||
Indirect evidence “Envirogen Group is a global leader in industrial water treatment and process filtration solutions.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 17 | 75 contacts → | ||||
Indirect 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 29, 2026Thanks. The Data Team will review it. | |||||
| 18 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 19 | 73 contacts → | ||||
Partial 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 29, 2026Thanks. The Data Team will review it. | |||||
| 20 | 70 contacts → | ||||
Indirect evidence “Welcome to Gel Engineering.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 21 | 64 contacts → | ||||
Indirect evidence “Glanville Environmental help commercial infrastructure owners reduce pollution and flood risk by inspecting and maintaining ageing drainage systems and installing new…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 22 | 59 contacts → | ||||
Indirect evidence “Waterco Datrys is a leading consultancy in water and environmental engineering, formed through the merger of Waterco and Datrys in 2024.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 23 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 24 | 51 contacts → | ||||
Indirect evidence “water2business is a leading retailer of water and waste water management solutions to businesses and organisations across England and Scotland.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 25 | 50 contacts → | ||||
Indirect evidence “ph Water technologies are one of the leading ‘Total Environment Solutions Companies' operating within the UK.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
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: wastewater consulting firms. 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 wastewater consulting firms.
- Partial evidence
- Its own public description names part of wastewater consulting firms, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name wastewater consulting firms. 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 427 wastewater consulting firms based in the United Kingdom
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Wastewater consulting firms based in the United Kingdom at a glance
As of Sep 29, 2026Companies by employee count
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 427 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 wastewater consulting firms, 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 “wastewater consulting firms”. 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 wastewater consulting firms), 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 wastewater consulting firms, 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, 3,533 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 29, 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 wastewater consulting firms, 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 wastewater consulting firms are there based in the United Kingdom?
RevenueBase identified 427 wastewater consulting firms 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?
RSK Group, headquartered in Helsby, tops this list with the largest team on record.
Which city has the most wastewater consulting firms?
London leads with 23 headquartered companies, followed by Newry (6) and Nottingham (6).
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 3,533 verified decision-maker contacts tracked across these 427 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 29, 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.
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