A water conservation device is disclosed. The water conservation device includes a membrane and an uninterrupted flange comprising a cross sectional cylindrical shape that is attached to an entire outer edge of the membrane. The membrane is configured to completely cover a top of a swimming pool skimmer access opening and further configured to accept an access lid of the swimming pool skimmer opening over the membrane wherein the access lid holds the water conservation device in place when the access lid is attached to the access opening by which the membrane acts to prevent water from expelling from the access lid.