Frustrated by discolored drinking water pouring from their taps, four Compton residents filed a class-action lawsuit late Monday against their water provider, Sativa Los Angeles County Water District. The lawsuit, filed at Los Angeles County Superior Court, accuses Sativa of failing to provide quality drinking water, misappropriating taxpayer dollars and causing a financial burden on its low-income customers in Compton and Willowbrook. It comes days before a crucial decision by county oversight officials on whether to dissolve the small public water district.