Landslips and heavy rainfall on Monday night disrupted the water treatment process in the Douglas Shire and a "dramatic" drop in some reservoirs prompted mayor Michael Kerr to warn residents to avoid unnecessary water usage.

"By working together we can overcome this water shortage and ensure the long-term sustainability of our water resources," Mr Kerr said.

Clean-up efforts in the region are continuing but Mr Kerr said the area is ready for tourists.

"There's a lot of work yet to be done but we're open for business and welcoming visitors," he said.

Tourism operators are also urging people not to cancel their holiday plans.

"It's great to see people walking the streets of Port Douglas again in board shorts and bikinis and enjoying this beautiful part of the world," Tourism Port Douglas chief executive Glen Hingley said.

More than 4200 property damage assessments have been completed since Jasper caused major flooding in the region.

Authorities have confirmed 12 homes were destroyed and 126 severely damaged.

Another 554 homes have been moderately damaged.

Australian Associated Press