Falmouth, located in Barnstable County, Massachusetts, is served by a public water system primarily using surface water sources. This system supplies water to over 97,000 residents through more than 21,900 connections. Understanding how perchlorate appears and behaves in this regional water system can help homeowners make informed choices about their household water treatment needs.
Myth: Detection of perchlorate in public water means levels exceed federal safety limits
Government sampling done by the Environmental Protection Agency (EPA) from 2001 to 2005 under the Unregulated Contaminant Monitoring Rule (UCMR1) shows no perchlorate detected above the EPA’s reporting level of 4.0 micrograms per liter in Falmouth’s water system. The EPA has not set a federal maximum contaminant level (MCL) for perchlorate. Therefore, any detection above this reporting level in other areas is simply a measurement point, not an indicator of violation or health risk. For Falmouth, the record shows no perchlorate measurement above that threshold.
Myth: Untreated perchlorate will cause immediate or severe damage to household water uses
Perchlorate can interfere with thyroid function if consumed at high levels over many years, but slow accumulation or low-level presence in water does not cause immediate damage to plumbing or common appliances. Over the long term, consistent exposure through drinking water at elevated concentrations could be of concern, which is why monitoring continues. However, effects related specifically to household water handling and fixtures are generally not the primary issue.
Myth: All faucets, appliances, and processes in the home are equally impacted by perchlorate
Perchlorate primarily affects the water designated for drinking and cooking because ingestion is the main exposure route concerning health. Faucets used for non-consumptive purposes, such as irrigation or laundry, are less critical from a perchlorate standpoint. The appliances most at risk of carrying perchlorate into the body are those delivering water for direct consumption.
Myth: Sampling data based on a few wells gives a complete picture of perchlorate in the area
The Falmouth Water Department’s monitoring included 28 perchlorate results from sampling conducted over several years. These represent measurements from the system-wide level, not individual private wells, so they provide a regional overview of perchlorate presence in the public water supply. While these samples cover public system sources adequately, a household with its own well water should arrange specific testing to determine its individual water condition.
Myth: The median perchlorate measurement can directly define presence in every home
Because no perchlorate was detected above the 4.0 micrograms per liter reporting threshold in public system samples, the median effectively confirms very low or nondetectable perchlorate concentration in the water system overall. However, individual household water may vary, especially if using a private well. Without a specific water test, assumptions cannot be made about any one home’s water quality regarding perchlorate.
Myth: Perchlorate originates only from industrial sources and cannot enter the water system naturally
In the Falmouth area, perchlorate can enter surface water supplies through various sources, including historical use of rocket propellants, fireworks, and certain fertilizers. These contaminants can migrate into watersheds and ultimately into public water supplies. Understanding these pathways helps explain why monitoring continues and why treatment options may be necessary for some households.
For homeowners concerned about perchlorate levels exceeding their current equipment’s capacity, a direct test of household water is the crucial next step to confirm exposure. Once the concentration is known, solutions such as the Pentair Perchlorate Filter, which ships ready to configure, can be considered to reduce perchlorate levels effectively at the point of use.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2003-06-02. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR1 monitoring (2001-2005) for FALMOUTH WATER DEPT (MA4096000), MA: 28 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level