Older and historic homes carry a unique set of PFAS exposure considerations that are distinct from the contaminated water supply concerns affecting all households. While source water contamination is the most common PFAS concern for homeowners, the materials and plumbing systems in older homes can introduce additional PFAS exposure pathways — and may interact with source water chemistry in ways that affect filtration system selection.
PFAS in Older Plumbing Materials
The plumbing systems of homes built before the 1980s may incorporate materials that either contain PFAS or were installed with PFAS-containing sealants and lubricants:
Teflon (PTFE) thread tape and pipe dope: Plumbers have used PTFE (polytetrafluoroethylene) thread seal tape — the white tape wrapped on pipe threads before connection — since the 1970s. PTFE itself is considered chemically inert and not a significant PFAS leaching source in finished form, but cutting and abrading PTFE tape during installation releases fine particles. In intact plumbing systems, PTFE thread tape is not a significant drinking water PFAS concern.
Historical plumbing sealants and lubricants: Some older plumbing products used PFAS-based compounds for lubrication and sealing. These products, if still present in older plumbing systems, could be minor PFAS sources — though this is rarely quantified in residential settings.
Lead pipes and PFAS interaction: Homes with lead service lines or lead solder (pre-1986 ban) face the compound challenge of both lead and PFAS in drinking water. Reverse osmosis systems address both contaminants simultaneously — an important advantage for older home plumbing remediation.
PFAS in Older Home Interior Materials
Beyond plumbing, older homes may contain PFAS in interior materials that contribute to indoor PFAS exposure through dust and air:
Stain-treated carpeting: Wall-to-wall carpeting installed in the 1970s–2000s was commonly treated with PFAS-based stain repellents (Scotchgard and similar products). Over time, PFAS migrate from carpet fibers into house dust, where they are inhaled and ingested — particularly relevant for infants and toddlers who have direct floor contact.
Non-stick cookware era: Homes that still use Teflon-coated non-stick pans from before the phase-out of long-chain PFAS (pre-2013) face ongoing PFAS volatilization during cooking, particularly at high temperatures. This is a minor contribution for most people but relevant in homes with very old cookware.
PFAS-treated upholstery and furniture: Furniture, draperies, and upholstery from certain eras were routinely treated with PFAS stain protectors. These shed PFAS into house dust over time.
Water Chemistry in Older Homes and Filter Selection
Older home water systems may present water chemistry challenges that affect filtration system selection and performance:
- Low water pressure from undersized mains or corroded distribution pipes affects RO system performance — booster pumps may be needed
- Higher turbidity or particulate load from older pipes requires pre-filtration to protect fine-pore membranes
- Elevated iron or manganese in older distribution systems can foul carbon and RO membranes
- pH extremes in older distribution systems affect PFAS adsorption characteristics
A Comprehensive Approach for Older Homes
For older home owners concerned about PFAS, a comprehensive assessment includes:
- Water testing for PFAS plus lead, iron, pH, and hardness to characterize source water fully
- Evaluation of water pressure for RO system compatibility
- Assessment of carpeting and upholstery for PFAS-treated materials
- Review of cookware age and type
- Installation of a whole-home or point-of-use filtration system specified for actual water chemistry
The compound benefits of addressing PFAS, lead, and other legacy contaminants simultaneously make comprehensive water testing and appropriately specified filtration especially valuable in older homes.