NR 811.65NR 811.65 Plant storage. The applicable design standards of ss. NR 811.63 and 811.64 shall be followed for plant storage. In addition:

NR 811.65(1)(1) Filter washwater tanks. Filter washwater tanks shall be sized, in conjunction with available pump units and finished water storage, to provide the backwash water required by s. NR 811.49. The design shall address the possibility of having to backwash more than one filter at a time, or several filters in succession.

NR 811.65(2)(2) Clearwell.

NR 811.65(2)(a)(a) Clearwell storage shall be sized, in conjunction with distribution system storage, to relieve the filters from the strain of fluctuations in water use or peak demands.

NR 811.65(2)(b)(b) When water storage is used to provide proper contact time for disinfection, documentation, including tracer testing, shall be provided to assure adequate detention time under all operating conditions. The department may require the installation of baffle walls or additional reservoir capacity if necessary to prevent short circuiting and to obtain adequate contact times.

NR 811.65(3)(3) Basins and wet-wells. Receiving basins, pump cans, and pump wet-wells for finished water or water to become finished water shall be designed as finished water storage structures.

NR 811.66NR 811.66 Distribution system storage. The applicable design standards of ss. NR 811.63 and 811.64 shall be followed for distribution storage. In addition:

NR 811.66(1)(1) Pressure variation. Distribution system storage facilities shall meet all the following requirements:

NR 811.66(1)(a)(a) Allowable head range. The maximum variation between high and low levels in storage structures which float on a distribution system may not exceed 30 feet during normal usage.

NR 811.66(1)(b)(b) Minimum and maximum pressures. The minimum and maximum pressure in service areas shall be 35 and 100 psi respectively at ground level.

NR 811.66(1)(b)1.1. In areas where a minimum of 35 psi cannot be maintained, a high pressure zone shall be established in the distribution system by means of booster pumps and related facilities or pressure boosting systems on individual service lines as required in subch. XI. The use of individual service line booster pumps shall be limited to the extent possible.

NR 811.66(1)(b)2.2. In situations where static pressures exceed 100 psi, pressure reducing devices may be required on mains in distribution systems having documented system deficiencies or problems due to high pressure such as main breaks and service line breaks.

NR 811.66 NoteNote: Section SPS 382.40 (7) (d) 2. a. requires a pressure reducing device to be installed to protect individual services when the incoming pressure exceeds 80 psig.

NR 811.66(2)(2) Drainage. The design shall allow draining of storage facilities for cleaning or maintenance while maintaining adequate positive pressure in the distribution system. The drains shall discharge to the ground surface as required in s. NR 811.64 (3).

NR 811.66(3)(3) Level controls. Adequate controls shall be provided to maintain required levels in distribution system storage structures. Level indicating devices shall be provided at a central location. Combination indicating and recording devices are recommended.

NR 811.67NR 811.67 Applicability. This subchapter covers water distribution systems for community water systems which are to be located in street rights-of-way or easements. Other piping systems shall be constructed in accordance with the requirements of ch. SPS 382.

NR 811.68(1)(1) Municipal ownership. The distribution system of a municipal water system shall be owned and maintained by the waterworks owner.

NR 811.68(2)(2) Municipally owned mains on private property. All water mains and other distribution system components owned by a municipal water system on private property shall be installed in permanent easements.

NR 811.68 NoteNote: To assure the use of approved materials and proper installation and maintenance, the department recommends that fire hydrants and water mains to be constructed on private property be installed in permanent easements and owned and maintained by the waterworks owner.

NR 811.68(3)(3) Privately owned looped mains and private water services requiring check valves. Water mains and water services to be connected to the publicly owned distribution system at more than one point may be privately owned and maintained provided that a check valve is installed on the water main at each point of connection to the distribution system to prevent water from flowing back into the distribution system. Each check valve shall be located in a manhole or vault and shall be immediately preceded and followed by a buried or exposed shut-off valve on the main. The water supplier shall have access to the manholes and valves for inspection purposes.

NR 811.68 NoteNote: A drain fitting may be added on the piping between the check valve and the gate valve on the public water system side of the check valve. The gate valve may be closed and the drain fitting opened to periodically check for leakage through the check valve. Refer to s. SPS 382.40 for standards for the construction of private water mains.

NR 811.685NR 811.685 Interconnections with other water sources. A water system owner shall obtain department approval prior to any interconnections between a public water supply system and another source of water in accordance with s. NR 810.15 (2), including interconnections solely for emergency backup purposes.