The Cook Islands government says it is yet to decide how to disinfect the water supply in Rarotonga.

The petition seeks greater transparency about the reticulation system, including how the government will disinfect the water, if at all.

A Cook Islands group says a lot more research is needed before using chemicals to disinfect the water supply on Rarotonga.

Concerns raised include the use of chlorine to disinfect the water, and the plan to charge residents for some of the water they use.