Ironing Out the Brown Water Problem

New York City rightfully touts the quality of its water supply. Even though the City’s water exhibits many desirable properties compared to countless other municipalities, brown water discoloration is a pesky fact of life for many New Yorkers. 

Iron in the City’s Water Mains is the Primary Source of Brown Water 

A review of the New York City 2018 Drinking Water Quality Report confirms the potential for recurring brown water problems ( According to the report, “Brown…water is often related to plumbing corrosion problems inside buildings [and] disturbance[s] to nearby water mains…Because the water mains are pressurized, a disturbance may stir up or resuspend sediments, which causes the water to be discolored.”

 The DEP report goes on to identify the most common source of this temporary and prolonged discoloration in the water: iron in the City’s aging water mains and water infrastructure. Anecdotal evidence from numerous brown water problems reported by our customers also suggests that iron enters the building from the City’s water mains, which are generally made of iron.  

Don’t Confuse the Primary Source of the Brown Water Problem 

Sometimes our customers confuse the true source of their brown water problem. Since many cold-water distribution systems are comprised of corroded-looking galvanized steel pipes, they conclude that the source of iron particulate is the older, corroded piping and fittings within their building’s cold-water distribution system. But this is not necessarily the case. 

In fact, most of our “problem-water” customers report discoloration in their hot water, not in their cold water.  Most hot-water distribution systems are comprised of copper and brass piping that does not contribute iron to the water. The condition of a building’s cold-water piping is not the primary culprit of their brown water problem.  Rather, iron enters the water distribution system from outside the building from the water main and then takes on a life of its own in the hot-water distribution system. 

Once the water enters a building’s hot-water distribution system, the iron oxidizes, expands, and becomes visible. A building’s maze of plumbing and related equipment creates an ideal environment for this particulate to settle; any change in water velocity can suspend the particulate and result in discoloration at kitchen and bathroom fixtures.

Frequently, we inspect a building’s water by connecting a white 10-micron filter cartridge at the water main. After 30 minutes, the filters are usually completely brown; the change in color is primarily attributable to iron and other sediments coming in from the street. 

Additional Contributing Factors to the Brown Water Problem

Water discoloration can vary widely by building and apartment in New York.  Contributing factors include, but are not limited to: i) condition of check valves on hot-water distribution systems, ii) physical location of the building and relative positioning on the water main, iii) ongoing street work, iv) design and layout of the building’s plumbing system, v) periodic rains, vi) occupancy of adjacent apartments, and vii) lack of ample hot water in the building. 

One Solution to the Brown Water Problem: “Blowout the Line” 

One solution for a building’s brown water problem is to flush and purge relevant branch lines in the distribution systems. Our mechanics work to disturb the particulate in water distribution risers and branch lines. The goal is to suspend the unwanted matter in the water long enough to rinse it to drain. Suspension of particulate can be achieved by many means. The ideal method varies by the specific situation. 

Methods employed in “blowing out a line’’  – as commonly called in plumbing parlance – include, but are not limited to: i) opening and closing valves at relevant fixtures, ii) applying pressure to branch lines and risers with an air compressor near problem fixtures, and iii) flushing water at relevant valves at the base of the hot-water distribution system. Once the particulate is suspended in the water, the water is rinsed to drain at a variety of strategic locations. 

The image below was taken during a service call in which our team purged the hot water lines of sediment and iron particulate; the bathtub was used as the  outlet for the dirty water.  

Why Should You Care About the Brown Water in Your Building? 
  • Sediment and dirt can collect in and impair the performance of expensive shower and kitchen fixtures. A clogged shower body or faucet can result in costly repair bills. Without addressing the issue at the source, the need for this type of repair can recur.
  • Particulate puts undue stress on expensive mechanical equipment in the basement, such as: i) house pumps, ii) boilers, and iii) water heaters. Replacement or repair of any of these items can be costly and disruptive to the building.
  • High amounts of particulate in the water can reduce chlorine’s effectiveness in combating bacteria.
  • No one likes to see brown water at their fixtures or in their bathtub before bathing. 

Flushing the water distribution system is an effective way to alleviate brown water problems temporarily; but it is not a permanent solution.