Hertfordshire is served by 2 different water companies, and a ban is set per company, not per county. The county is genuinely the wrong unit of answer: your postcode decides.
Affinity Water could not be confirmed, so check with them directly. Cambridge Water could not be confirmed, so check with them directly. Which of these applies at your address depends on which one bills you.
We could not confirm Affinity Water’s current status from their own page, so we are not asserting a restriction. Check with your supplier before using a hosepipe.
Check with your supplier
Areas covered: The Affinity Water Central region: Bedfordshire, Berkshire, Buckinghamshire, Essex, Hertfordshire, Surrey and parts of north and west London.
We could not confirm Cambridge Water’s current status from their own page, so we are not asserting a restriction. Check with your supplier before using a hosepipe.
Check with your supplier
Areas covered: The Cambridge Water supply area: Cambridgeshire with parts of Bedfordshire and Hertfordshire, about 350,000 households.