Ben Lomond Water chief officer Barry Cash said the restrictions were a water conservation measure aimed at reducing non-essential use of water by 10-20 per cent.

"We are asking affected customers to conserve water and show consideration to other users," Mr Cash said.

He said the restrictions were designed to reduce demand, and manage the supply of water to residents and businesses, particularly in outlying and higher areas which may experience low water pressure.

•Gardens and lawns; manual watering systems can only be used between the hours of 6am and 8am and 8pm and 10pm. Automatic watering systems can only be used between the hours of midnight and 4am. Hand held hoses with a trigger nozzle, buckets or watering cans may be used at any time.

•Sporting Grounds; same limitations apply as gardens and lawns.

•Paving, concrete and other hard surfaces; hosing is banned except for construction purposes or for health and safety hazards.

•Vehicles; a bucket, high pressure cleaning device or commercial car wash can be used at any time for vehicle washing. A hand-held hose fitted with a trigger nozzle can only be used for pre-rinsing and rinsing.

•Pools and spas; to fill or top up a new or existing pool or spa with a capacity of 2000 litres or less, a hand-held hose fitted with a trigger nozzle, a watering can or a bucket must be used. Pools and spas of greater than 2000 litres capacity must only be filled with approval from Ben Lomond Water.