Usually no — distilled and purified water are generally personal expenses, not FSA eligible, unless a provider documents a specific medical need. A home filtration or reverse-osmosis system, however, can be eligible with a Letter of Medical Necessity.
Quick answer
Generally not eligible. Store-bought distilled or purified water is treated like ordinary bottled water — a personal expense. A filtration system that produces clean water at home is the eligible route, with a Letter of Medical Necessity.
"Purified" water has been treated to remove contaminants to a defined purity (often by reverse osmosis, deionization, or distillation). "Distilled" water is one type of purified water, boiled to steam and recondensed, leaving minerals behind. Both describe the water — a consumable — rather than a medical device.
Because they are consumable drinking water, distilled and purified water sit in the same category as bottled water: a personal grocery expense under IRS Publication 502, not a qualified medical expense. Buying jugs of distilled water for convenience does not qualify. Narrow medical exceptions exist but must be documented by a provider and confirmed by your plan — never assumed.
If you want purified water for health reasons, the device that produces it can be the qualified expense. An under-sink reverse osmosis system produces purified-grade drinking water on demand and can be FSA/HSA eligible with a Letter of Medical Necessity — far cheaper over time than buying jugs, and it removes the recurring cost and plastic waste. For whole-home needs, see whole-house eligibility.
Occasionally a provider recommends distilled water for a specific device or condition — some medical equipment manufacturers specify it, for instance. Whether that makes a purchase reimbursable is a case-by-case determination by your provider and plan administrator, and it does not generalize to everyday drinking water. When in doubt, ask rather than assume.
Distillation and reverse osmosis both produce very low-mineral, high-purity water; RO does it on demand at the tap without boiling, which is why a home RO system is the practical eligible route to purified water. Spring water, by contrast, is simply bottled source water — a personal expense like any other bottled product.
Buying jugs of distilled or purified water is an ongoing, non-eligible cost; an at-home RO system is a one-time, potentially eligible purchase that produces comparable water for pennies per gallon afterward. Over a few years the home system is almost always cheaper — see the savings math and RO eligibility.
Treat store-bought distilled or purified water as a personal grocery expense, and treat the device that purifies water at home as the potentially eligible medical purchase. If purity matters for a documented reason, put your pre-tax dollars toward the equipment, not the jugs.
Generally no. Distilled water is a consumable personal expense, like bottled water, unless a provider documents a specific medical need and your plan confirms it.
Usually not on its own. Purified water is treated as a personal grocery expense. A device that purifies water at home can be eligible with a Letter of Medical Necessity.
A home reverse-osmosis or filtration system can qualify with a Letter of Medical Necessity, produces purified-grade water on demand, and costs far less over time than buying water.
