The gadgets are used to calibrate computer models that predict where flooding may occur under extremely heavy rainfall.
Sewerage planning manager David Martin said: “The severe flooding in Bournemouth last year bordered on a major emergency and we are doing all we can to ensure that should such a storm event happen again, the effects are not as damaging.
“Building new infrastructure to cope with storms is costly and disruptive to local communities so these computer models will help us understand where best to increase capacity and optimise where investment goes.”
The water company is working with Bournemouth Borough Council, which has responsibility for surface water flooding.
Martin added: “The new monitors will help ourselves and Bournemouth Borough Council to understand the interaction between flow above and below the ground so we can effectively design joint capacity improvement schemes where there is shared responsibility.”
It plans to build computer models at 55 more locations in its region by 2015 and move on to lower risk catchments by 2020.