The Home Office's central London HQ has switched off its water fountain to comply with Thames Water's hosepipe ban.
The water feature outside the Marsham Street building was confirmed by a spokeswoman for the department.
The ban, which affects all of Thames Water's 8.8 million customers, prevents its water being used to fill or maintain an ornamental fountain.
Water which usually falls from rectangular pools either side of the building's main entrance has been switched off under the terms of section 76 of the Water Industry Act 1991.
The UK's biggest water company said it was constantly reviewing the ban.
"We won't keep the ban on for a moment longer than necessary but a few wet weeks doesn't make up for the driest two-year period on record," a Thames Water spokeswoman said.
The six-storey headquarters of the Home Office, which cost £311 million in a PFI deal in 2005, were designed by Sir Terry Farrell, architect of MI6's landmark headquarters on the south bank of the Thames, and Charing Cross railway station.
Number 2 Marsham Street replaced three 20-storey concrete tower blocks built for the Department for the Environment, which were considered one of London's biggest eyesores and nicknamed The Three Ugly Sisters.
