The water company closed all visitor sites in March to help limit the spread of coronavirus.
It is now carrying out a careful, gradual reopening of sites during this month and June based on Government advice.
It hopes to open larger sites including at the beginning of June, but only if it can be done safely.
The first sites to reopen include Trimpley Reservoir, near Bewdley, and Priorslee Reservoir in Telford.
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Severn Trent will monitor and review each site once it has been opened. If it is confident visitors and communities are safe, and social distancing can be maintained, it will look at opening others.
Each site will use different measures specific to their circumstances, but will include things like closure of some footpaths, one-way systems, closure of play areas, reduced toilet facilities and hand sanitiser stations in car parks and at toilets.