Households in some parts of the East Midlands will bebanned from using hosepipes from today.
Seven water companies across the country, including Anglian Water, are introducing restrictions on water use following one of the driest two-year periods onrecord.
Customers who breach the ban could face a fine of up to £1,000.
Most reservoirs are now below normal levels and river flows are decreasing, according to the Environment Agency. It says water firms should do more to tackle leakage rates.
Anglian Water was among a number of firms which failed to meet leakage targets last year. The company says supplies have not been able to be restocked because of a significant rainfall shortage in the past two winters.
Peter Simpson, managing director of Anglian Water, said: "Two dry winters have prevented rivers, reservoirs and aquifers from refilling with the water we treat and supply the rest of the year, especially during the hotter months when demand rises."