Design and Construction Standards - Tualatin Valley Water District

Water Service Connections Section 6ii.Where the pressure exceeds 80 psi, the District may require Developers toinstall a pressure reducing facility such as a vault housing pressurereducing valves (PRVs) on the main, or individual pressure regulatingdevices on each service line on the customer’s side of the meter asrequired by plumbing code.2. Provision of Water Metersi. Each individual tax lot (residential) shall have a separate water meter.ii. If the structure on a single tax lot is a duplex or triplex, individual meters foreach unit will be installed upon request at the time that the dwelling isconstructed.iii. Tax lots with more than four dwelling units are considered “multi-familyuse,” which is in the District’s commercial class and shall require a mastermeter.3. Meter Sizesi. The size of water meters shall be based on the total demand as reflectedby the number of fixture units in the plumbing system. The meter size shallbe determined according to methods and procedures outlined in Section610.4 and 610.8 or Section 610.5 of the Uniform Plumbing Code (UPC).ii. Where practical, 5/8-inch and 3/4-inch meters will be served by a 1-inchcopper service line with double, or U-branch, service connections. The twometers will be installed in separate meter boxes located adjacent to the lotline.iii. 1-inch and larger meters will be served from a single service line connectedto the water main.Contact the District Engineer for requirements for meters larger than two inches.4. Location of Metersi. The District generally places meters at the edge of the public right-of-waynear the intersection of a property line. The District has the authority tomove or change placement of water meters within the PUE.ii. Meters 1-inch and smaller shall be located in the PUE adjacent to the rightof-wayat the property line.iii. Meters 1½-inch and larger shall be located in a vault on the Developer'sproperty in a dedicated easement adjacent to the street right-of-way. Theeasement dimensions shall extend ten feet beyond each outside wall of themeter vault.iv. No other utilities shall be located within three feet of a meter or serviceline.v. Private Streets. Individual meters serving homes on private streets shall beinstalled in clusters or banks adjacent to the entrance of the private street.Refer to Standard Details 7, 7D, 7P, 7PD, and 9.5. Backflow prevention assemblies are required on all meters 1½ inches and largerand for any size meter serving a high hazard facility. See Chapter 8 for furtherinformation on backflow assemblies.TVWD Water System Standards June 2012 Page 6-2