1 CHAPTER 17. NONPOTABLE RAINWATER CATCHMENT SYSTEMS. General. Sizing. Rainwater catchment system distribution Applicability. The provisions of this CHAPTER shall piping for indoor applications shall be sized as outlined in this apply to the installation, construction, alteration, and repair code for sizing potable water piping. The design and size of of rainwater catchment systems for nonpotable applications rainwater drains, gutters, conductors, and leaders shall com- listed in Section ply with CHAPTER 11 of this code. Irrigation. Rainwater catchment systems used Rainwater Catchment System Materials. Rain- for lawn irrigation are not covered under this CHAPTER . water catchment system materials shall comply with Section through Section Combination Systems.
2 Rainwater catch- ment systems used for lawn irrigation in combination Water Supply and Distribution Materi- with any uses listed in Section shall meet the als. Rainwater catchment water supply and distribution requirements of this CHAPTER . The irrigation system shall materials shall comply with CHAPTER 6, as amended in be separated by an air gap or proper backflow protection this code, and the requirements of this code for potable as required for potable water. water supply and distribution systems, unless otherwise provided for in this section. Rainwater Catchment System Drainage Nonpotable Rainwater Catchment Systems. Materials. Materials used in rainwater catchment General. The installation, construction, alteration, drainage systems, including gutters, downspouts, con- and repair of rainwater catchments systems intended to sup- ductors, and leaders shall be in accordance with CHAPTER ply uses such as water closets, urinals, trap primers for floor 11, as amended in this code, and the requirements of this drains and floor sinks, industrial processes, water features, code for storm drainage.
3 Vehicle washing facilities, cooling tower makeup and similar Storage Tanks. Rainwater storage tanks uses shall be approved by the commissioner. shall comply with Section , as amended in this Plumbing Plan Submission. No permit for a code. rainwater catchment system shall be issued until complete Collections Surfaces. The collection sur- plumbing plans have been submitted and approved by the face shall be constructed of a hard, impervious material. commissioner in accordance with Minnesota Rules, part , subpart 6. Rainwater Catchment System Color and Marking Information. Rainwater catchment systems shall System Changes. No changes or connections shall have a colored background in accordance with Section be made to either the rainwater catchment system or the Rainwater catchment systems shall be marked, in lettering in potable water system within a site containing a rainwater accordance with Section , with the words: CAUTION: catchment system requiring a permit without approval by the NONPOTABLE RAINWATER WATER, DO NOT DRINK.
4 Authority Having Jurisdiction. Design and Installation. Connections to Potable or Reclaimed (Recy- cled) Water Systems. Rainwater catchment systems shall Outside Hose Bibbs. Outside hose bibbs have no direct connection to a potable water supply or alter- shall be allowed on rainwater piping systems. Hose bibbs nate water source system. Potable or reclaimed (recycled) supplying rainwater shall be marked with the words: water is permitted to be used as makeup water for a rainwa- CAUTION: NONPOTABLE WATER, DO NOT. ter catchment system provided the potable or reclaimed (recy- DRINK and Figure cled) water supply connection is protected by an air gap or reduced-pressure principle backflow preventer in accordance with this code.
5 An automatic means to supply the rainwater catchment system with makeup water shall be installed when there is insufficient rainwater to meet the required demand or due to system failure. Initial Cross-Connection Test. Where a portion of a rainwater catchment system is installed within a building, a cross-connection test is required in accordance with Sec- tion , as amended. Before the building is occupied or the system is activated, the plumbing contractor shall per- form the initial cross-connection test in the presence of the Authority Having Jurisdiction. The test shall be ruled suc- cessful before final approval is granted. FIGURE 2015 MINNEOSTA PLUMBING CODE 127. NONPOTABLE RAINWATER CATCHMENT SYSTEMS. Deactivation and Drainage for Cross- Below Grade.
6 Rainwater storage Connection Test. The rainwater catchment system and tanks installed below grade shall be structurally the potable water system within the building shall be pro- designed to withstand anticipated earth or other vided with the required appurtenances ( , valves, air or loads. Holding tank covers shall be capable of sup- vacuum relief valves, etc.) to allow for deactivation or porting an earth load of not less than 300 pounds per drainage as required for a cross-connection test in accor- square foot (lb/ft2) (1465 kg/m2) where the tank is dance with Section designed for underground installation. Below grade Collection Surfaces. Rainwater catchment rainwater tanks installed underground shall be pro- systems shall collect rainwater only from roof surfaces.
7 Vided with manholes. The manhole opening shall be Rainwater catchment systems shall not collect rainwater located not less than 4 inches (102 mm) above the from: surrounding grade. The surrounding grade shall be sloped away from the manhole. Underground tanks (1) vehicular parking surfaces;. shall be ballasted, anchored, or otherwise secured, (2) surface water runoff; to prevent the tank from floating out of the ground (3) bodies of standing water; or where empty. The combined weight of the tank and (4) similar nonroof surfaces. hold down system shall meet or exceed the buoy- ancy force of the tank. Prohibited Discharges. Overflows and bleed-off pipes from roof-mounted equipment Drainage and Overflow. Rainwater and appliances, condensate, and other waste disposal storage tanks shall be provided with a means of shall not discharge onto roof surfaces that collect draining and cleaning.
8 The overflow drain shall not rainwater for rainwater catchment systems. be equipped with a shutoff valve. The overflow out- let shall discharge in accordance with this code for Minimum Water Quality. The minimum storm drainage systems. Where discharging to the water quality for rainwater catchment systems shall meet storm drainage system, the overflow drain shall be the applicable water quality recommendations in Table protected from backflow of the storm drainage sys- tem by a backwater valve or other approved method. TABLE (A) Overflow Outlet Size. The Measure Limit overflow outlet shall be sized to accommodate Turbidity (NTU) <1 the flow of the rainwater entering the tank and E. coli (MPN/100 mL) not less than the aggregate cross-sectional area of inflow pipes.
9 Odor Non-offensive Opening and Access Protection. Temperature (degrees Celsius) MR. (A) Animals and Insects. Rain- Color MR. water tank openings shall be protected to pre- pH MR vent the entrance of insects, birds, or rodents MR = measure and record only into the tank and piping system. Screen installed Treatment: on vent pipes, inlets, and overflow pipes shall 5 micron or smaller absolute filter be corrosion-resistant and have an aperture of Minimum .5-log inactivation of viruses not greater than 1/16 inch ( ) and shall be Rainwater Storage Tanks. Rainwater stor- close-fitting. age tanks shall be constructed and installed in accordance (B) Human Access. Rainwater with Section through Section tank access openings exceeding 12 inches (305.)
10 Construction. Rainwater storage mm) in diameter shall be secured to prevent shall be constructed of solid, durable materials not tampering and unintended entry by either a subject to excessive corrosion or decay, watertight lockable device or other approved method. and suitable for rainwater storage. Marking. Rainwater tanks shall be per- Location. Rainwater storage tanks shall manently marked with the capacity and the lan- be permitted to be installed above or below grade. guage: NONPOTABLE RAINWATER. Where Above Grade. Above grade storage openings are provided to allow a person to enter the tanks shall be of an opaque material, approved for tank, the opening shall be marked with the following aboveground use in direct sunlight or shall be language: DANGER-CONFINED SPACE.