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New York State Verified Proprietary Stormwater Management Practices

The following lists the verified proprietary stormwater management practices (SMP) that meet the performance criteria for redevelopment applications as defined in the New York State Stormwater Management Design Manual (Design Manual). The New York State Department of Environmental Conservation listing of stormwater treatment technologies is, at this time, based on the verifications conducted by other environmental regulatory agencies.


The following tables provide information on three types of proprietary practices: Hydro Dynamic Systems, Wet Vaults, and Media Filters.

No proprietary product is identified for infiltration and or quantity control systems for redevelopment applications because such practices are generally considered acceptable as standard practices if designed in accordance with the standards defined in the Design Manual. Use of manufactured infiltration systems is considered a standard practice as long as all the required elements and design guidance defined in the Design Manual are followed. Use of underground storage systems is also considered a standard practice for the purpose of detention and attenuation to meet water quantity control requirements.


Chapter 9 of the New York State Stormwater Management Design Manual provides a general outline for design and sizing of the verified practices. Since sizing criteria is integral to the verified performance of manufactured practices, designers should refer to the capacities and flow rates associated with the models (sizes) of the manufactured SMPs identified by the verification source. Appropriate sizing and allowable flow rates are provided in Table 1, Sizing Method, by referencing directly to the product model sizing developed by verification source.

In addition to meeting water quality performance goals, proprietary practices must be sized to capture and treat the WQv resulting from the contributing drainage area.

For practices with a volume-based sizing approach, the practice must be sized to capture and treat 75 % of the WQv as defined in Chapter 4 of the Manual. For flow through systems, the practice must be sized to treat the water quality volume based on its associated peak rate as defined in Chapter 4 and Appendix B of the Manual. All flow through systems, which do not have a built in bypass mechanism, must be designed off-line and the installation must include flow diversion that protects the practice from exceeding design criteria.

All proprietary practices proposed for use on a redevelopment project must be evaluated and accepted for removal efficiency using one of the following stormwater management practice evaluation systems: the U.S. Environmental Protection Agency (EPA) Environmental Technology Verification Program, the State of Washington Technology Assessment Protocol - Ecology (TAPE), the Technology Acceptance Reciprocity Partnership Protocol (TARP) - (PDF, 800 KB), New Jersey Corporation for Advance Technology (NJCAT) or the State of Maryland Proprietary Practice acceptance program. See Table 1 for list of practices. (Note: The Department reserves the right to accept or reject any proprietary practice that has been evaluated and accepted by one of the evaluation systems listed above.)

All proprietary practices proposed for use in new construction are considered to be in deviation from the State Standards. In order to use a proprietary practice in new construction, the removal efficiency of the proposed proprietary practice must be greater than or equal to the performance criteria required by the State of New York (i.e. 80% TSS removal and 40% phosphorus removal). The removal efficiency must be verified using field studies (include records of in ground installation and maintenance) and the practice must have been in the ground for at least one year at the time of monitoring. The performance criteria must be verified and certified by one of the sources listed above and then accepted by the Department.

All proprietary practices accepted for use on a redevelopment project may also be used for pretreatment, provided the practice has been designed in accordance with the Design Manual.

Table 1. Verified Proprietary Stormwater Management Practices (* see Stormwater Manufactured Treatment Devices link below for additional practices)
Company Product Type Source Design Method Outside Links for Sizing Method (source, product)
Americast Americast's filterra® system Filtering WADOE Flow through Americast's filterra® - (PDF, 100 KB)
Contech Stormwater Solutions StormFilter (ZPG media) Filtering ETV Flow through ETV, StormFilter (ZPG media) - (PDF, 157 KB)
Crystal Stream Technologies Crystal Stream Water Quality Vault Wet Vault ETV Flow through USEPA, ETV Program Crystal Stream Water Quality Vault - (PDF, 1.18 MB)
WSDOT Ecology Embankment (Chapter 5) Filtering WADOE Filt./Infilt. WADOE, Ecology Embankment (Chapter 5) - (PDF, 162 KB)
ZETA Technology, Inc. ARKAL Pressurized
Stormwater Filtration System
Filtering EPA ETV Flow through

ARKAL Pressurized Stormwater Filtration System - (PDF, 236 KB)

* Stormwater Manufactured Treatment Devices which have received Interim Certification from the New Jersey Department of Environmental Protection

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