ABOUT 200,000 South Australian households will receive a nine per cent cut in their electricity bills from January 1, 2013.

The state government recently negotiated the price cut for about 20 per cent of the state's electricity customers, signed up to AGL's standing contract.

Small businesses will receive a 4.5 per cent cut under the same deal, after the state government agreed to lock in the new prices for two years, and fully deregulate the electricity market.

Most South Australian households will also benefit from a new water security rebate, which will automatically be applied to the water bills of eligible customers from the start of 2013.

Properties using up to 120 kilolitres of water each year will receive a $45 rebate, while those using more than 120 kilolitres will receive $75 back.