If your concern is the water you drink and cook with — not the whole house — an under-sink or reverse osmosis system is the affordable, eligible answer. Here are the best point-of-use picks for 2026.
Quick take
Eligible — with a Letter of Medical Necessity. Under-sink and RO systems are the lowest-cost eligible route and the best fit for renters and drinking-water-only concerns. See RO eligibility.
For point-of-use we weighted contaminant reduction (certifications to NSF/ANSI standards, especially NSF/ANSI 58 for RO), footprint under a sink, filter cost and lifespan, and a working HSA/FSA path. These systems treat one tap rather than the whole home — if you need whole-home coverage, see the whole-house roundup instead.
Compact under-sink RO delivering bottled-quality drinking and cooking water. The lowest-cost eligible option and renter-friendly.
~$399
Check price →RO membranes reduce lead, nitrates, PFAS, and many dissolved contaminants — the issues that most often drive a medical-necessity case for drinking water.
Point-of-use
Point-of-use systems can move with you and need no whole-home plumbing — ideal for apartments. See our renter-friendly guidance.
Flexible
RO removes minerals along with contaminants, so some units remineralize for taste; it also uses a storage tank and a little wastewater, which is why it suits drinking and cooking rather than whole-home supply. Replacement filters and membranes can be reimbursed on the same basis — keep receipts per the documents checklist.
RO forces water through a semipermeable membrane that blocks dissolved contaminants, typically across several stages: sediment and carbon pre-filters, the RO membrane itself, and a final polishing filter (some add remineralization). The result is very low-contaminant water at the tap. Certification to NSF/ANSI standards NSF/ANSI 58 is the signal that a system's RO claims are independently verified.
Plan on pre/post filter changes every 6–12 months and a membrane every 2–3 years — all reimbursable on the same basis as the system when documented. RO also produces some wastewater and stores treated water in a small tank, so flow is slower than a faucet filter. None of this affects eligibility; it just confirms RO is for drinking and cooking, not whole-home supply. For the bigger picture, weigh it against a whole-house system.
Clean drinking water at the tap for around $399 — the most affordable eligible system, through the TrueMed checkout.
Check price →Yes, with a Letter of Medical Necessity. RO is a strong fit when the documented concern is in your drinking water, such as lead or nitrates.
Under-sink is cheaper and treats one tap; whole-house treats every tap and makes a broader medical-necessity case. Choose based on whether your concern is drinking water only or whole-home.
Yes. Point-of-use systems need no whole-home plumbing and can move with you, making them ideal for apartments.
