I researched this thoroughly in 2022. This is what I found:
"Hosepipe bans" don't exist anymore, they were replaced by Temporary Use Bans (TUBs)
And they CAN include commercial use, depending on what the water company decides.
But, this is a critical point, the actual law states that in a Temporary Use Ban, there is a statutory exemption for Health and Safety use. Section 12 of the
The Water Use (Temporary Bans) Order 2010 says : (note section 12(2) )
12.—(1) The category of use in section 76(2)(i) of the Act applies only to the cleaning of the external walls or windows of domestic premises.
(2) Using a hosepipe to clean the walls or windows of domestic premises for health or safety reasons is not to be treated as falling within the category of use in that section.
(3) In that section, “domestic premises” means—
(a)a building used principally as a dwelling or dwellings;
(b)a garage, shed, outbuilding or other building or structure used or enjoyed in connection with a building mentioned in sub-paragraph (a); or
(c)a wall or other means of enclosure within the curtilage of a building mentioned in sub-paragraph (a).
[Read it here:
https://www.legislation.gov.uk/uksi/2010/2231/article/12 ]
If you're wondering if this H&S exemption applies to us, then look at this
Managing through drought: code of practice and guidance for water companies on water use restrictions 2023(All UK water companies are signatories to this)
[Read the full thing here :
https://ukwir.org/update-to-the-drought-code-of-practice-2013]
Relevant statutory and non statutory exemptions are listed on page 73 and 81 and especially page 128 and 188
Apparently, in the 2011-2012 drought, some of the water companies told window cleaners to go back to using ladders. Window cleaners (it was actually representations made by The BWCA) pointed out to them that this would breach the Work at Height regulations, as a safer alternative could be used. The result was that, in drafting the new Tempoary Use Bans, (again at the urging of the BWCA) , they decided that protecting people from the serious risk of falls from height trumped saving the tiny amount of water (relatively speaking) that window cleaners use.
A good result.