Ammonia shows up in water from a few different directions — naturally occurring decomposition, agricultural or septic runoff, and in some municipal systems, as an ingredient added on purpose. The EPA hasn't set a federal limit for it specifically, which makes a water test the only real way to know your level.
The EPA has not established a federal Maximum Contaminant Level (MCL) for ammonia in drinking water on its own. That doesn't mean it's never worth addressing — it means there's no single enforceable number to compare your water against, so context matters.
In well water, ammonia usually traces back to decomposing organic matter, agricultural fertilizer runoff, or a nearby septic system. In municipal water, it can show up for a different reason entirely: many utilities deliberately combine a small, controlled amount of ammonia with chlorine to produce chloramine, a disinfectant that lasts longer in the distribution system than chlorine alone. (See our Chlorine & Chloramine page for more on that process.)
Reverse osmosis membrane filtration reduces a broad range of dissolved compounds, ammonia included, as water is forced through a semi-permeable membrane under pressure — giving you a consistent result regardless of why the ammonia is there in the first place.
Learn MoreNote: this is addressed by our reverse osmosis drinking-water system specifically — our whole-house filtration systems are not designed or certified to remove it.
We'll test it for free and show you exactly what a system would remove.
At the low levels typically found in treated tap water, ammonia is mostly a taste and odor issue rather than an acute health hazard. The EPA hasn't set a formal limit for it specifically, so a water test is the best way to know your actual level and whether it's worth addressing.
Some municipal utilities combine a small, controlled amount of ammonia with chlorine to create chloramine, a secondary disinfectant that holds up longer through the distribution system than chlorine alone. It's a treatment choice made at the utility level, not a sign of contamination.
Not reliably. Our reverse osmosis system is the equipment built to meaningfully reduce it — whole-house carbon and sediment filtration isn't designed for this specific job.