About Mountain Pure Water
Great water shouldn’t require a chemistry degree.
By Jason Preston, Founder
We make industry-leading filtration understandable and easy to choose. We start with your situation, recommend the right system, and explain exactly why it works. The systems themselves come from one of the most credible engineers in the business.
The engineer behind your water
Meet Nelson McIlveen
Mountain Pure Water doesn’t make the systems we sell — we curate them. And the line we chose, Sentry H2O, was built by a man who has spent his whole life making things that can’t fail.
Not a marketer who found water — an engineer who built it
Nelson D. McIlveen didn't stumble into water filtration. He's a career engineer and tool-maker who ran the manufacturing divisions of Fortune 500 companies across the U.S., Asia and Mexico before he ever started a business of his own. When he talks about how a filter is built, it's because he's spent a lifetime building things that have to work.
He owns the factory — that’s the part nobody else can say
In 2006 Nelson founded Celtic Plastics, a Tempe, Arizona injection-molding company that makes precision parts for the aerospace, military and water-filtration industries. Most water-filter brands buy their housings from a third party. Nelson makes his, giving Sentry H2O direct oversight of the housings it uses instead of outsourcing them.
It started, like most good things, at his own kitchen sink
Sentry H2O began when Nelson grew concerned about the water his own family was drinking. So he did the obvious thing for an engineer with a factory: he built a multi-stage filtration line, backed it with independent lab testing, and manufactured it in the United States — the line Mountain Pure Water carries today.
And when it mattered, he showed up
After the 2023 Norfolk Southern train derailment in East Palestine, Ohio, Nelson sent 2,000 under-sink systems to the community — the first 500 free to any resident who showed a water bill. That’s not a marketing campaign. That’s a guy who builds clean-water systems deciding that people who needed clean water should have it.
2,000
Under-sink systems sent to East Palestine, Ohio after the 2023 derailment
500
Given free to any resident who showed a water bill — first come, first served
Why this matters to you: when the person who designs the product also owns the factory that builds it, nothing gets watered down to hit a price point. You’re buying water systems from an engineer who answers to his own standards — and Mountain Pure Water’s job is simply to help you pick the right one and understand why it works.
What Mountain Pure Water adds
More than a storefront
Education first
We tell you why a system is right for you — not just what it costs. The manufacturer site won’t.
Engineer-built, factory-owned
Every product is genuine Sentry H2O engineering — built in Nelson’s own injection-molding facility, sold and supported under Mountain Pure Water.
Testing, plainly labeled
Published third-party lab results are linked from our Science page. The systems are tested to NSF standards; certification documents are being finalized, so we do not call them NSF certified.
30-day guarantee + lifetime housing warranty
Try any system for 30 days. Housings and durable hardware are covered for life; filters and filter media are excluded.
See the proof
Don’t take our word for it — see the lab results.
Every claim on this site traces back to independent lab testing, published in plain English next to the technologies it's compared against.
See the comparison