PROGRESS THROUGH COOPERATION

November 9, 2005

Re: Water System Pressures

Dear Valued Customer:

We have recently received some concerns and questions from customers over high water pressures within their interior plumbing. There are numerous factors that affect pressures throughout the Commission’s water distribution system, such as: elevation, pump runs, system demands, proximity to elevated storage, etc. Water pressures on the Commission’s distribution system may vary from 25 psi to 170 psi. Due to these possible high pressures, our system is designed and built to withstand pressures of 200 psi.

Due to the possibility/presence of high pressures in water systems throughout the nation, the International Plumbing Code Section 604.8 requires “where water pressure within a building exceeds 80 psi static, an approved water-pressure reducing valve conforming to ASSE 1003 with strainer shall be installed to reduce the pressure in the building water distribution piping to 80 psi static or less.”

The Commission recommends that you have the pressure tested at your home or business and make the necessary improvements to ensure the internal pressure does not exceed 80 psi. The Commission does not and will not take any responsibility for any damage that may result from high interior water pressures.

Should you have any questions with regards to the water pressures at your point of connection with the system, please don’t hesitate to give us a call at 359-8373.

P. O.Box 1966 . Lexington, S. C. 29701 . Tel. (803) 359-8373 .  Fax (803) 359-6553

SECTION 604
DESIGN OF BUILDING WATER
DISTRIBUTION SYSTEM

604.8 Water-pressure reducing valve or regulator. Where water pressure within a building exceeds 80 psi (552 kPa) static, an approved water-pressure reducing valve conforming to ASSE 1003 with strainer shall be installed to reduce the pressure in the building water distribution piping to 80 psi (552 kPa) static or less.

Exception: Service lines to sill cocks and outside hydrants, and main supply risers where pressure from the mains is reduced to 80 psi (552 kPa) or less at individual fixtures.

604.8.1 Valve design. The pressure-reducing valve shall be designed to remain open to permit uninterrupted water flow in case of valve failure.