The failure of Forsyth County to strike a new water contract with the City of Cumming could leave some 47,000 water customers with “dramatically higher” rates, the city’s mayor said.

The two have reached an impasse after now five rounds of negotiations:

At stake is the water future of some 170,000 county residents and the economic development of what has been Georgia’s fastest-growing county in recent years.

Cumming, one of only four jurisdictions with permits to draw water from Lake Lanier, is in a strong bargaining position. It’s 25-year contract with Forsyth County is set to expire May 26. …

The county’s latest offer seeks reduced rates for treated water and triple the rate for raw water. If accepted by the city, it could save county customers about $28 million over the next 15 years compared with the current contract, county officials said.

If the new offer is bounced, Forsyth must begin considering alternatives — piping water from neighboring Gwinnett County — that would all cost the metro municipality tens of millions.