Drinking Water Disinfections (AWWA C651 Compliant)
Before any new or repaired water main, service line, or building water system can be placed into service in New York City, it must be disinfected — and that disinfection must meet the requirements of AWWA C651 (Standard for Disinfecting Water Mains) or AWWA C652 (Standard for Disinfection of Water Storage Facilities). The NYC Plumbing Code and NYC regulations are explicit: new and repaired potable water piping must be properly disinfected and bacteriologically cleared before connection to the distribution system or before first use.
Acqua Treat has been performing potable water disinfections for contractors, plumbers, and building owners across New York City since 1982. We handle the full process from start to finish — flushing, chemical treatment, contact time, sampling, lab analysis, and all required documentation.
When Is Disinfection Required?
Under the NYC Plumbing Code (Section 610) and NYC regulations, potable water disinfection is required for:
New water mains and service piping before being placed into service
Repaired or replaced sections of existing water mains
Water systems that have been out of service for an extended period
New building domestic water risers and distribution piping
Any water system where contamination is suspected or confirmed
Water storage tanks and vessels (per AWWA C652)
Licensed master plumbers and general contractors are responsible for ensuring that disinfection is completed and documented before sign-off. If you are not sure whether your project requires disinfection, call us — we can review the scope and confirm what's needed.
Our Disinfection Process — How It Works
We follow the AWWA C651 continuous feed or slug method, using sodium hypochlorite solution to achieve the required 200 ppm (parts per million) initial chlorine concentration with a minimum contact time of three hours. Our process for a standard new-construction pipe disinfection:
Pre-flush — the system is flushed with potable water to remove construction debris, pipe oils, solder flux, and sediment.
Chlorine introduction — sodium hypochlorite solution is introduced to achieve a 200 ppm free chlorine concentration throughout the piping.
Contact time — the chlorinated water is held in the system for a minimum of 3 hours (24 hours for heavily contaminated or complex systems).
Final flush — the system is flushed until chlorine residual returns to the normal distribution system level (typically below 4 ppm).
Bacteriological sampling — we collect water samples at representative locations and submit them to a certified laboratory.
Results and documentation — once samples return with satisfactory results (absence of total coliform and E. coli), we provide a written disinfection report suitable for submission and project closeout.
If initial samples fail, we perform 1 round of re-sampling at no additional charge after corrective action flushing. We stay with the project until the system is cleared.
Who We Work With
We work directly with licensed master plumbers (LMPs), general contractors, mechanical contractors, and building owners throughout all five boroughs. Our clients include:
Licensed master plumbers performing new construction rough-in and tie-ins
General contractors on residential and commercial new construction projects
Mechanical contractors on building renovation projects requiring water system tie-ins
NYC School Construction Authority (SCA) projects
NYC Department of Design and Construction (DDC) projects
DASNY, CUNY, and other municipal construction programs
Building owners undertaking gut renovations with new plumbing
Documentation We Provide
Every disinfection we perform includes a complete documentation package:
Written disinfection report documenting: date, location, pipe sections treated, chlorine concentration used, contact time, and flush volumes
Certified laboratory bacteriological results (total coliform and E. coli absence confirmation)
Chain of custody documentation for all samples
Photo documentation of sampling locations where required
Certification letter signed by Acqua Treat confirming AWWA C651 compliance
This documentation package is designed to satisfy NYC DEP, NYC DOB, and project engineer requirements for closeout and sign-off. We can also coordinate directly with your project engineer or inspector of record if needed.