N.Y. Comp. Codes R. & Regs. tit. 10, § 128-3.7 – Sewerage systems, service connections and discharges to sewerage systems.

(a) Combined sewerage systems are prohibited from discharging within the watershed.
(b) A new service connection to a sewerage system is prohibited where the wastewater treatment plant to which the sewerage system has been connected and which discharges within the watershed has had a SPDES flow parameter violation in the prior 12 months, or where the additional flow from the new service connection will cause or can be expected to cause such wastewater treatment plant to have a SPDES flow parameter violation.
(c) All new service connections shall be tested as required by and in accordance with the standards set forth in “Design Standards for Wastewater Treatment Works, Intermediate Sized Sewerage Facilities,” New York State Department of Environmental Conservation (1988), and the standards in “Recommended Standards for Wastewater Facilities,” the Great Lakes—Upper Mississippi River Board of State Public Health and Environmental Managers, Sections 33.92-33.94 (1990). A copy of the results of the tests shall be forwarded to the department as soon as they are available.
(d) Except for the owner of an individual or two-family residence, the owner of any property which will be served by a new service connection to a sewerage system, or by any alteration or modification of a service connection to a sewerage system, shall submit all plans or designs for such service connection or such alteration or modification to the department prior to or simultaneously with the delivery of the notice to the department required under paragraph (1) of this subdivision. The owner of an individual or two-family residence to be served by a new service connection to a sewerage system, or by an alteration or modification of a service connection to a sewerage system, shall not be required to submit the plans or designs for such service connection or such alteration or modification to the department, unless specifically requested by the department. If so requested, such owner shall submit such plans or designs to the department prior to or simultaneously with the delivery of the notice to the department required under paragraph (1) of this subdivision or, if the request is made by the department after such notice has been given, within 10 days after such request has been made.
1. (1) The owner of any property which will be served by a new service connection to a sewerage system, or by an alteration or modification of a service connection to a sewerage system, shall notify the department 48 hours prior to the installation of such service connection or of such alteration or modification, and provide an opportunity to the department to observe the work. If required or requested pursuant to this subdivision, the owner shall submit to the department all plans or designs for such service connection or for such alteration or modification prior to or simultaneously with the delivery of the such notice to the department.
(e) The design, construction and plans for a new sewerage system shall require the review and approval of the department. Any proposed alteration or modification of a sewerage system, including a sewerage system that is a noncomplying regulated activity, shall require the review and approval of the department.
1. (1) The department may require an engineering report, construction plans and specifications, and any environmental assessments and determinations in compliance with article 8 of the Environmental Conservation Law when reviewing any application pursuant to this subdivision for a new sewerage system, or a proposed alteration or modification of a sewerage system.
(f) The criteria used by the department to approve any new sewerage system or the portion of any sewerage system which is being altered or modified, shall be all applicable requirements of law, including the standards set forth in the following documents:
1. (1) “Design Standards for Wastewater Treatment Works, Intermediate Sized Sewerage Facilities,” New York State Department of Environmental Conservation (1988);
2. (2) “Recommended Standards for Wastewater Facilities,” the Great Lakes—Upper Mississippi River Board of State Public Health and Environmental Managers (1990).
(g) All sewerage systems connected to a wastewater treatment plant which discharges within the watershed shall be designed, operated and maintained in such manner as to prevent inflow or infiltration which causes either:
1. (1) the SPDES authorized flow limit of the wastewater treatment plant to be exceeded; or
2. (2) the strength of the sewage influent to the wastewater treatment plant to be diluted to a level that adversely affects the efficacy of the SPDES permitted and department approved treatment process.
(h) All sewerage systems shall be designed, operated and maintained to prevent exfiltration from such systems.
(i) The owner or operator of a facility which disposes of wastes regulated pursuant to the Federal Categorical Pretreatment Standards, 40 CFR part 403, shall submit three copies of the engineering report, plans and specifications, prepared by a licensed design professional, in compliance with 40 CFR parts 403, 406-471 and any applicable local regulations, to the department for its review and approval.