Cost issues   The initial cost of implementing a Greywater system can range from approximately $1,600.00 to $6,000.00 , however there are long-term benefits which offset start up costs. The price of water can vary from $0.50/1000 gallons to $28.00/1000 gallons with an addition charge of $0.20/1000 to $1.20/1000 gallons for sewage treatment of all water leaving the site. Determined by complexity of the Greywater system, the cost of water will decrease over time because less water is being used. Greywater system separates and uses the water, less water is returned to the sewage treatment plant. Overall, less water is being used, while at the same time, less water is being sent to the sewage plant for treatment.