Aqwest will give away a washing machine to promote National Water Week 2017 from October 15 to 21.
There will also be an esky and a soft cooler as second and third prizes.
This year for the first time, Bunbury residents will be asked to include their water meter reading on their entry coupon.
"We really want to encourage people to get into the habit of reading their meter regularly, because by getting to know your water usage, you can very easily tell when meter numbers suddenly increase, which could indicate a hidden leak," Aqwest Chief Executive Officer Brad Bevis said.
"Hidden leaks often go undetected until people receive their water bills and they get a shock when they are suddenly faced with a very large bill to pay.
"At the same time, a lot of water has been wasted and we all need to be vigilant to ensure we have a water resource for the future.
"The competition is a great way to educate people about how to read their meter and track their water usage, learn about water conservation and go in the draw to win some great prizes at the same time."
They must include their meter reading and Aqwest Assessment number on the entry form with their name, address, telephone and email address and either post it to Aqwest, email their details, or drop the coupon in to the office at MacKinnon Way.
The closing day is 5pm, Thursday, October 19.