UK SIC 2007 · 36000
Water collection, treatment and supply (SIC code 36000)
Water collection, treatment and supply is UK SIC code 36000. It sits in division 36 (Water collection, treatment and supply) of the SIC 2007 list. On the August 2026 Companies House register, 1,660 active UK companies list 36000 among their SIC codes. 1,501 of them list it first.
Division 36: Water collection, treatment and supply
A single code division, 36000, and a surprisingly large one given that UK water supply is dominated by a small number of regional monopolies. The company count is high because the public record captures the structure around those businesses: holding companies, financing vehicles, subsidiaries, and the growing number of new appointments and variations operating in the competitive retail market. Most file the code in first position.
Related SIC codes
Who prospects SIC 36000 companies
Selling into this division means selling either to the utilities themselves, which is a long procurement cycle, or to the far more numerous corporate entities around them. Engineering and civils contractors, leak detection and metering technology, water quality laboratories and asset management software all have buyers here. The public record is at its most useful for mapping group structures, because officer and address overlap makes the relationships between entities visible.
Lead generation for commercial & B2B services →How to read SIC 36000
SIC 36000 is a five-digit code, and the digits are not arbitrary. The first two, 36, are the division, water collection, treatment and supply. Add the third and you have group 360; the fourth narrows it to a class, and the fifth to the subclass, which is the level Companies House actually asks a company to pick. The whole division sits under section E, water supply, sewerage and waste management, the broadest tier there is. Reading a code left to right therefore goes from a whole sector down to one activity.
More on how SIC 36000 is built
A company chooses its own codes when it incorporates and can change them on any confirmation statement. It may list up to four, and Companies House does not check whether they are right. That is why 36000 is worth reading as a claim the company made about itself rather than as a verified fact, and why the first-position and any-position counts above differ.
Measured on the August 2026 register, the busiest registered-office post towns for 36000 are London (240), Glasgow (31), Manchester (31), Birmingham (23) and Leeds (20). Those are registered-office locations, which is where the paperwork sits rather than necessarily where the work happens, so treat them as where to start looking rather than as a service area.
Using SIC 36000 as a filter
1,660 companies is 0.03 per cent of the 5,190,464 active companies on the UK register, and ranks 36000 most used of the 1 codes we track in division 36. That is the pool before any filter. Whether it is a big market for you depends on what you sell, but it is the number every other filter on this page cuts down from.
More on filtering by SIC 36000
Almost everybody who uses 36000 means it: 1,501 of 1,660 companies put it first, leaving only 159 carrying it as a secondary code. That makes it an unusually clean filter. You can match on the code alone and trust that the companies you get really are in this line of work.
These companies are spread out. London is the largest single cluster at 14 per cent and the top five post towns together hold only 21 per cent, so the remaining 79 per cent sits across the rest of the country. A regional filter narrows this list without gutting it, which makes it a reasonable code to work territory by territory.
In practice the code on its own is rarely the whole filter. Pair 36000 with an incorporation date to catch companies in their first months, when they are still choosing suppliers, or with a filing deadline to reach them while the year end is on their mind. A worked example for this code: 36000, registered office in London, incorporated in the last ninety days, which turns a 1,660 company pool into a list you can write to in an afternoon. Add the poor-website filter if what you sell is a website, or a recent change of officer if you sell to whoever just took the job. Every company you pull carries the Companies House record, the director's name, a verified website and a verified email, and the ones we cannot complete are not charged.
Where SIC 36000 clusters in the UK
ACTIVE COMPANIES BY REGISTERED-OFFICE POST TOWN · COMPANIES HOUSE REGISTER, AUGUST 2026
SIC 36000 companies, as leads
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About SIC 36000
How many UK companies use SIC code 36000?
1,660 active UK companies list 36000 (Water collection, treatment and supply) among their registered SIC codes. Each company may register up to four. Of those, 1,501 put it first. The figures come from the August 2026 Companies House register snapshot, and count active companies only.
Why are there over a thousand companies in water supply?
Because the public record counts legal entities, not utilities. A single water company typically sits inside a group with holding companies, financing subsidiaries and service entities, and the retail market has added further licensed suppliers. The operational businesses are a small fraction of the count.
Do private borehole and water treatment firms use this code?
Some do, though many treatment and filtration businesses fit better in a division 28 machinery code or a division 43 installation code. If you are selling to treatment specialists rather than to supply undertakings, check those divisions too rather than relying on 36000 alone.
Find UK SIC 36000 companies
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