D.C. Mun. Regs. tit. 12, r. 12-F1301
Scope. The provisions of Chapter 13 shall govern the materials, design, construction and installation of systems for the collection, storage, treatment and distribution of nonpotable water. The use and application of nonpotable water shall comply with laws, rules and ordinances applicable in the District of Columbia.
Water quality.Nonpotable water for each end use application shall meet the minimum water quality requirements as established for the intended application by the laws, rules and ordinances applicable in the District of Columbia. Where nonpotable water from different sources is combined in a system, the system shall comply with the most stringent of th e requirements of this code that are applicable to such sources.
Residual disinfectants. Where chlorine is used for disinfection, the nonpotable water shall contain not more than 4 ppm (4mg/L) of chloramines or free chlorine when tested in accordance with ASTM D 1253. Where ozone is used for disinfection, the nonpotable water shall not contain gas bubbles having elevated levels of ozone at the point of use.
Exception:Reclaimed water sources shall not be required to comply with these requirements.
Filtration required.Nonpotable water utilized for water closet and urinal flushing applications shall be filtered by a 100-micron or finer filter.
Exception:Reclaimed water sources shall not be required to comply with these requirements.
Signage required.Nonpotable water outlets shall be identified at the point of use for each outlet with signage that complies with Section 608.8.1.
Strike Section 1301.4 of the International Plumbing Code in its entirety and insert new Section 1301.4 in its place in the Plumbing Code to read as follows:
Permits. A building permit and pertinent trade permits in accordance with Section 105 of the Building Code shall be required for the construction, installation, alteration and/or repair of nonpotable water systems. This section shall not apply to above-grade, self-contained rainwater collection tanks or rain barrels that meet the following conditions:
Strike Section 1301.7 of the International Plumbing Code in its entirety and insert new Section 1301.7 in its place in the Plumbing Code to read as follows:
Potable water connections. Where a nonpotable water system described in this chapter requires makeup water from the potable water system, the water makeup piping shall be protected against backflow by an approved air gap.
Approved components and materials. Piping, plumbing components and materials used in collection and conveyance systems shall be manufactured of material approved for the intended application and compatible with any disinfection and treatment systems used.
Insect and vermin control. The system shall be protected to prevent the entrance of insects and vermin into storage tanks and piping systems. Tank vent openings and overflow outlets shall be screened with a corrosion-resistant screen of not less than 16 by 20 mesh per inch (630 by 787 mesh per m) or shall be protected by an approved equivalent alternative method. Screen materials shall be compatible with contacting system components and shall not accelerate the corrosion of system components.
Exception: Tank vent overflow outlets on above-grade, self-contained rainwater collection tanks or rain barrels that meet the following conditions:
Strike Section 1301.8 of the International Plumbing Code in its entirety and insert new Section 1301.8 in its place in the Plumbing Code to read as follows:
Freeze protection. Where sustained freezing temperatures occur, provisions shall be made to keep storage tanks and the related piping from freezing. This provision is not intended to apply to rain leaders installed on the exterior of buildings.
Exception: Above-grade, self-contained rainwater collection tanks or rain barrels that meet the following conditions (a) have an individual capacity of 150 gallons (568 L) or less and (b) are not connected to a distribution piping system.
Strike Section 1301.9.2 of the International Plumbing Code in its entirety and insert new Section 1301.9.2 in its place in the Plumbing Code to read as follows:
Nonpotable water storage tanks. Nonpotable water storage tanks shall comply with Sections 1301.9.1 through 1301.9.11.
Sizing. The storage tank holding capacity and the associated water collection and conveyance system shall be designed based on the anticipated demand, the capacity of the makeup water supply, and the capacity of the available sources of nonpotable water to be collected for reuse.
Location. Above-grade storage tanks shall be protected from direct sunlight and shall be constructed using opaque, UV-resistant materials such as, but not limited to, heavily tinted plastic, fiberglass, lined metal, concrete, or wood, or shall be painted to prevent algae growth, or shall be provided with specially constructed sun barriers including, but not limited to, installation in garages, crawl spaces or sheds. Above-grade and underground storage tanks and their manholes shall not be located directly under any soil pipe, waste pipe or any source of contamination.
Exception: Above-grade, self-contained rainwater collection tanks or rain barrels that meet the following conditions:
Strike Section 1301.9.7 of the International Plumbing Code in its entirety and insert new Section 1301.9.7 in its place in the Plumbing Code to read as follows:
Materials. Water collected on site shall be stored in an approved tank constructed of durable, nonabsorbent and corrosion-resistant materials. The storage tank shall be constructed of materials compatible with any disinfection systems used to treat water upstream of the tank and with any systems used to maintain water quality in the tank. Wooden storage tanks that are not equipped with a makeup water source shall be provided with a flexible liner.
Foundation and supports. Storage tanks shall be supported on a firm base or foundation capable of withstanding the weight of the storage tank when filled to capacity. Storage tanks shall be supported by structural systems designed in accordance with the Building Code.
Ballast. Where the soil can become saturated, an underground storage tank shall be ballasted, or otherwise secured, to prevent the tank from being dislodged by buoyancy when empty. The combined weight of the empty tank and hold down ballast shall exceed the buoyancy force of the tank when immersed in water. Where the installation requires a foundation, the foundation shall be flat and shall be designed to support the weight of the storage tank when full, consistent with the bearing capacity of the soil.
Structural support. Where installed below grade, storage tank installations shall be designed to withstand the lateral and superimposed structural loads without damage and with minimal deformation when the tank is empty or filled with water.
Makeup water. Where an uninterrupted supply is required for the intended application, potable or reclaimed water shall be provided as a source of makeup water for the storage tank. If potable water is used for the makeup water supply, it shall be protected against backflow by an approved air gap. A full-open valve located on the makeup water supply line to the storage tank shall be provided. Inlets to the storage tank shall be controlled by fill valves or other automatic supply valves installed to prevent the tank from overflowing and to prevent the water level from dropping below a predetermined point. Where makeup water is provided, the water level shall not be permitted to drop below the source water inlet or the intake of any attached pump.
Overflow. The storage tank shall be equipped with an overflow pipe having a diameter not less than that shown in Table 606.5.4. The overflow pipe shall be protected from insects or vermin and shall discharge in a manner consistent with storm water runoff requirements of the District of Columbia. The overflow pipe shall discharge at a sufficient distance from the tank to avoid damaging the tank foundation or the adjacent property. Drainage from overflow pipes shall be directed to prevent freezing on roof or other walkways. The overflow drain shall not be equipped with a shutoff valve. Cleanouts shall be provided on each overflow pipe in accordance with Section 708.
Access opening. Not less than one access opening shall be provided to allow inspection and cleaning of the tank interior. Access openings shall have an approved locking device or other approved method of securing the access opening. Underground storage tanks located outside of the building shall be provided with a manhole either not less than 24 inches (610 mm) square or with an inside diameter not less than 24 inches (610 mm). Manholes shall extend not less than 4 inches (102 mm) above ground or shall be designed to prevent water infiltration. Finished grade shall be sloped away from the manhole to divert surface water. Manhole covers shall be secured to prevent unauthorized access. Service ports in manhole covers shall be not less than 8 inches (203 mm) in diameter and shall be not less than 4 inches (102 mm) above the finished grade level. The service port shall be secured to prevent unauthorized access.
Exceptions:
Strike Section 1301.9.11 of the International Plumbing Code in its entirety and insert new Section 1301.9.11 in its place in the Plumbing Code to read as follows:
Exception: Underground storage tanks less than 800 gallons (3028 L) in volume shall not be required to be equipped with a manhole, but shall have a service port not less than 8 inches (203 mm) in diameter.
Venting. Storage tanks shall be provided with a vent sized in accordance with Table 906.5.1, based on the aggregate maximum flows of all tank influent pipes. The reservoirvent shall not be connected to sanitary drainage system vents. Vents shall be protected from contamination by means of an approved cap or U-bend installed with the opening directed downward. Vent outlets shall extend not less than 4 inches (102 mm) above grade or as necessary to prevent surface water from entering the storage tank. Vent openings shall be protected against the entrance of vermin and insects in accordance with the requirements of Section 1301.7.
Draining of tanks. Where tanks require draining for service or cleaning, tanks shall be drained by using a pump or by a drain located at the lowest point in the tank. The tank drain pipe shall discharge as required for overflow pipes and shall not be smaller in size than specified in Table 606.5.7. Not less than one cleanout complying with Section 708 shall be provided on each tank drain pipe.
Marking and signage. Each nonpotable water storage tank shall be marked with its rated capacity. The contents of nonpotable water storage tanks shall be identified with signage that reads as follows: "CAUTION: NONPOTABLE WATER - DO NOT DRINK." Where an opening is provided that could allow the entry of personnel, the opening shall be marked with signage that reads as follows: "DANGER - CONFINED SPACE. " Markings shall be indelibly printed on the tank or on a tag or sign constructed of corrosion-resistant waterproof material that is mounted on the tank. The lettering of the signage required by this section shall be not less than 0.5 inch (12.7 mm) in height and shall be of a color that contrasts with the background on which it is applied.
Storage tank tests. Storage tanks shall be tested in accordance with the following:
inspection.
Exception: Above-grade, self-contained rainwater collection tanks or rain barrels that meet the following conditions:
Strike Section 1301.10 of the International Plumbing Code in its entirety and insert new Section 1301.10 in its place in the Plumbing Code to read as follows:
System abandonment. If the owner of an on-site nonpotable water reuse system or rainwater collection and conveyance system elects to cease use of such system, the owner shall first obtain approval from the code official to abandon the system. If the owner of such system fails to properly maintain it, the code official is authorized to order abandonment or repair of the system, as deemed appropriate, in the interest of protection of public health and balancing equities, taking into account prior commitments and obligations of the owner and the benefit of maintaining such system. Above-grade, self-contained rainwater collection tanks or rain barrels that meet the following conditions are not required to comply with this section:
When the code official approves or orders an on-site nonpotable water reuse system or rainwater collection and conveyance system to be abandoned, such abandonment shall comply with the following:
Trenching requirements for nonpotable water piping.Nonpotable water collection and distribution piping and reclaimed water piping shall be separated from the building sewer and potable water underground piping by 5 feet (1524 mm) of undisturbed or compacted earth. Nonpotable water collection and distribution piping shall not be located in, under or above cesspools, septic tanks, septic tank drainage fields or seepage pits. Buried nonpotable water piping shall comply with the requirements of Section 306.
Exceptions:
Outdoor outlet access. Sillcocks, hose bibbs, wall hydrants, yard hydrants and other outdoor outlets supplied by nonpotable water shall be located in a locked vault or shall be operable only by means of a removable key.
D.C. Mun. Regs. tit. 12, r. 12-F1301