STATE OF NEW YORK ________________________________________________________________________ 1175 2025-2026 Regular Sessions IN SENATE January 8, 2025 ___________ Introduced by Sen. MATTERA -- read twice and ordered printed, and when printed to be committed to the Committee on Environmental Conservation AN ACT to amend the environmental conservation law, in relation to rain- water harvesting The People of the State of New York, represented in Senate and Assem- bly, do enact as follows: 1 Section 1. Article 15 of the environmental conservation law is amended 2 by adding a new title 35 to read as follows: 3 TITLE 35 4 RAINWATER HARVESTING 5 Section 15-3501. Purpose. 6 15-3503. Rainwater harvesting feasibility. 7 15-3505. Rainwater harvesting conveyance. 8 15-3507. Rainwater harvesting pretreatment. 9 15-3509. Rainwater harvesting treatment. 10 15-3511. Rainwater harvesting landscaping and vegetation. 11 15-3513. Rules and regulations. 12 § 15-3501. Purpose. 13 Rainwater harvesting practices, when designed to temporarily store 14 stormwater runoff for detention or re-use through retention, may assist 15 in meeting stormwater runoff reduction goals. 16 Rainwater harvesting is the capture, conveyance, and storage of 17 precipitation from impervious surfaces, typically rooftops, primarily 18 for re-use, rather than infiltration or release into a waterway. Rainwa- 19 ter harvesting has minimal site requirements compared to other stormwa- 20 ter management practices and may be used in residential and industrial 21 settings for any volume of rooftop runoff, if sized appropriately. 22 Rainwater harvesting may be used on sites where dense development, 23 pollutant hotspots, or soil conditions preclude the use of infiltration 24 or other stormwater management practices. The use of rainwater harvest- 25 ing reduces the amount of stormwater runoff entering the drainage system EXPLANATION--Matter in italics (underscored) is new; matter in brackets [] is old law to be omitted. LBD03701-01-5S. 1175 2 1 and local receiving waters as well as reducing or delaying peak flow 2 rates. It is important to have well-defined operation and maintenance 3 procedures for any rainwater harvesting system, in order to provide 4 adequate storage capacity for subsequent storm events. 5 Storage tanks for harvested rainwater may be sited above- or below- 6 ground, indoors or outdoors, or on rooftops of buildings that have been 7 designed to bear the load of rainwater storage. The main components of a 8 rainwater harvesting system include: a contributing rooftop surface; a 9 conveyance system of gutters, downspouts, and pipes; screening or pre- 10 treatment filter and clean-out; a watertight storage container; an over- 11 flow pipe; an access hatch; and an extraction system, such as a spout or 12 pump. Additional components may include a first flush diverter, pres- 13 sure tank, and backflow prevention device. 14 Rain barrels are commonly used to store harvested rainwater in small- 15 scale residential settings, while above- or below-ground cisterns are 16 more commonly used in larger-scale industrial settings. Rain barrels are 17 above ground storage tanks generally holding fifty to eighty gallons, 18 but may hold up to two hundred gallons. Cisterns are sealed tanks, which 19 may be above or below ground and generally hold two hundred to ten thou- 20 sand gallons. While carefully managed rain barrels can be a viable means 21 of stormwater runoff volume reduction for very small volumes of rainwa- 22 ter, this standard is intended to be applied to the larger storage 23 volumes and more robust management strategies that are possible only 24 with cisterns. 25 Harvested rainwater is often well-suited for reuse in landscape irri- 26 gation and other non-potable uses, including in toilets and urinals, as 27 well as HVAC make-up water, topping off swimming pools, and washing 28 cars. In the state, reuse of harvested rainwater for purposes other than 29 irrigation is largely unaddressed by current state regulations or local 30 codes. Because of this lack of specific rainwater harvesting guidance, 31 some jurisdictions have regulated harvested rainwater as reclaimed 32 water, resulting in stringent requirements that make reusing harvested 33 rainwater challenging. The practicality of rainwater reuse will need to 34 be evaluated on a case-by-case basis. 35 § 15-3503. Rainwater harvesting feasibility. 36 The following design elements are required when implementing rainwater 37 harvesting practices to capture and re-use stormwater runoff: 38 1. Rainwater harvesting shall be limited to rooftop runoff. 39 2. Rainwater storage shall be designed to capture at least 0.2 inches 40 of rainfall from the contributing rooftop. 41 3. An application area or water reuse shall be identified that is 42 sufficient to reuse the stormwater volume stored within a week at an 43 application rate of one inch per week over the irrigation period from 44 May through September. 45 4. For underground storage tanks, the bottom of the tank shall be 46 above groundwater level, and the top of the tank shall be below the 47 frost line. Storage tanks that are above ground or not able to be 48 buried below the frost line shall be appropriately insulated or discon- 49 nected during the winter months to protect the system from freezing. 50 § 15-3505. Rainwater harvesting conveyance. 51 1. Gutters shall be hung at a minimum of one-half percent for two- 52 thirds of the length and at one percent for the remaining one-third of 53 the length, and shall be set and sized to properly capture, contain, and 54 convey the one inch storm event at a rate of one inch per hour.S. 1175 3 1 2. Overflow runoff shall be safely conveyed to a suitable, down-gra- 2 dient location such as a buffer area, open yard, grass swale, or second- 3 ary treatment practice, as applicable. 4 3. Overflow conveyance and tank siting shall be designed to prevent 5 ponding or soil saturation within ten feet of building foundations, and 6 underground cisterns shall be sited at least ten feet from building 7 foundations. 8 4. Systems shall be designed around a water budget analysis that iden- 9 tifies how water will be used to ensure that storage capacity in the 10 system will be available for subsequent runoff events. 11 § 15-3507. Rainwater harvesting pretreatment. 12 1. Pretreatment of rainwater shall be provided in the form of a filter 13 or screen to prevent leaf litter, sediment, and other debris from enter- 14 ing the storage tank. First flush diverters, vortex filters, roof wash- 15 ers, and leaf screens are acceptable forms of pretreatment. The 16 pretreatment shall be installed either in the gutter or downspout or at 17 the inlet to the storage tank, with proper design for clean-out. 18 Depending on the desired use for the rainwater, additional filtration 19 may be needed or desired. 20 2. Mosquito screening with a one millimeter mesh size shall be 21 installed at openings to prevent mosquitos from entering the storage 22 tank. 23 § 15-3509. Rainwater harvesting treatment. 24 1. A water budget analysis shall be provided to the department that 25 identifies how water will be used, to ensure that the system will be 26 available for subsequent runoff events. 27 2. Storage tanks shall be watertight and shall be composed of and 28 sealed with water safe, non-toxic substances. 29 3. Rainwater shall not be harvested from the following roof types: tar 30 and gravel, asbestos shingle, and treated cedar shakes. In addition, 31 rainwater shall not be collected from roofs with metal flashing that 32 contains lead. 33 § 15-3511. Rainwater harvesting landscaping and vegetation. 34 Stormwater shall not be diverted to a rainwater harvesting system 35 until the overflow conveyance and application areas have been stabilized 36 with vegetation. 37 § 15-3513. Rules and regulations. 38 The commissioner shall promulgate all rules and regulations necessary 39 for the implementation of this title. 40 § 2. This act shall take effect on the ninetieth day after it shall 41 have become a law. Effective immediately, the addition, amendment and/or 42 repeal of any rule or regulation necessary for the implementation of 43 this act on its effective date are authorized to be made and completed 44 on or before such effective date.