New Hampshire water profile
Too little of New Hampshire reports to describe New Hampshire
1 of New Hampshire's 706 active community water systems has a current nitrate result here — 0.1% of the state. That is not enough to describe a state, and this page does not try.
The 1 system that does report is below 3.00 mg/L as N. That is a fact about 1 system. It is not a fact about New Hampshire, and the difference matters: a sample this small can look calm while the unsampled majority does not, or look alarming because the systems that report are the ones with a reason to.
The missing systems are a sourcing gap on this end. They have not been shown to be low, and they have not been shown to be high — they have not been read.
New Hampshire is left unshaded on the national map, because shading it would put a number on the map that the underlying reporting cannot support. Coverage is expected to grow as more sources are gathered, and this page will say something different when it does.
The 1 New Hampshire system that does report →
Coverage is uneven between states and is shown as it is rather than smoothed over. Where it is incomplete, and why.
Meanwhile
What the rest of the country reports
The national map covers 38,762 community water systems across 47 states. See where human impact is clear, or read what the breaks at 1, 3, 5 and 10 can and cannot tell you. The general science — how nitrate moves, why some ground is vulnerable, and why the legacy lingers — is on Where nitrate comes from.