Soon Bermuda will know exactly what ends up in house tanks as improvements are planned for the island’s rooftop rain collection method.

Tariq Smith, an environmental scientist and water engineer, last week told Hamilton Rotary Club about what goes into house tanks in the first bout of rain after a dry spell.

“After five to six weeks of no rain, imagine the amount of leaves, sediment, bird droppings and lizard droppings,” he said. “It washes all that sediment and debris into your tank.”

A pipe-based gadget equipped with a rubber ball, known as the first flush diverter, will be tried out later this summer under a collaboration between Mr Smith’s firm, Koom Consulting, and the Bermuda Institute of Ocean Sciences – with financing through the Ministry of Education.

The aim of the device is to dump the first wash of sediment-laden rain collected on the typical rooftop before allowing clean water into the storage tank below the house.

Mr Smith told the club: “One of the main challenges is there’s very little data on sediment accumulation in our tanks – there’s very little information on what’s in our tanks and what we are drinking.”

The contents of tank silt, which can include particles settling from traffic and industrial use, can inform guidelines and standards, including how often tanks in certain areas of the island should get cleaned.

The first flush diverter is designed for houses with exterior pipes, while the down pipes in Bermuda’s houses are typically inside the walls.

Mr Smith told the club on Tuesday: “At this stage we are going to be installing a preliminary prototype.

“If this first phase is successful, we’ll need to adapt this to Bermudian architecture. It could be a little expensive or might be reasonably priced.”

A planning phase launched last summer is expected to wrap up by September.

Mr Smith said he hoped to see a design suited for Bermuda by the end of 2023.

BIOS began a home water survey in 2013 to trace how bacteria such as salmonella can build up in tanks.

A 2018 study led by Koom Consulting highlighted a need among some residents to understand the health risks from contamination of the “raw“ water kept in tanks, according to the Department of Health.