Corrosive Consequences of Low-Flow Toilets | SageWater
The Energy Policy Act of 1992, which became law in 1994, mandates a maximum flush volume of 1.6 gallons for toilets manufactured and installed after this date. Prior to enactment of the Energy Policy Act, toilets used from 3.5 to 5 gallons per flush.  According to the EPA, the water saved through implementation of the act has had a number of positive environmental consequences, including restoration of wetlands and fisheries and savings in the amount of energy needed to pump water.[1]

While intended to yield environmental benefits, the Energy Policy Act has unfortunately resulted in some unintended consequences on the nation’s plumbing systems.

In older properties, the majority of drain pipes are galvanized steel or cast iron, which over time become corroded and rusty.  When an older property upgrades to low-flow toilets, there is often not enough water to keep waste and other disposables moving through the pipes. Further, as a result of the low-flow requirements, the ratio of water to sewage has changed, making the flow of waste thicker and slower, allowing the build up of bacteria, and producing a corrosive acidic gas that also causes corrosion in the piping system.

Often, if the pipe is already corroded, toilet paper and waste can get caught on the rough corroded surface, further exacerbating the problem.  In the end, reduced flow and more concentrated waste result in a rapid acceleration of the corrosion process, ultimately leading to clogs, back-ups, broken pipes and leaks.

Corroded drain pipes cause the overwhelming majority of water drainage problems in multi-family apartments and condominiums. In addition, the installation of low flow fixtures by condo owners (at their expense) is inadvertently having a negative impact on the communities drain lines (HOA expense).  If your property is experiencing systemic flow problems, drainage leaks, odors, or other problems with your drain, waste and vent piping system, it might be time to check your pipes before your plumbing system fails.  For garden style communities, upgrading to PVC can provide a reliable waste piping system.  For high-rise properties, the newer cast iron is more corrosive resistant than the older materials, and promises years of maintenance-free plumbing.