Proposals to contract out operation of Douglas County's Lake Tahoe water systems won't save much money.Both the Tahoe Douglas District and the Kingsbury General Improvement District responded to a county request for proposals to run the three county owned water companies at the Lake.Last year, county commissioners expanded the Tahoe Douglas District's list of services in anticipation of the proposal.In a report to commissioners, Public Works Director Carl Ruschmeyer said that the best of the proposals would save customers $6 a month while cutting the staffing by a fraction."Overall, an evaluation of the proposals determined that only a marginal cost …