Two walkers fall severely ill after drinking filtered burn water on West Highland Way

Two walkers on the West Highland Way were rescued after becoming violently ill on consecutive days after drinking filtered water from a burn near Conic Hill. The men were reported to be German and American, and both were vomiting after relying on portable filters that did not prevent sickness.

The incident landed amid a wider cluster of illness reports on the route. In the month before May 8, 2025, at least nine walkers passing through Rowardennan and the Balmaha area suffered vomiting and diarrhoea after drinking river water, even though all nine said they had filtered it first. Three of those walkers said they drank from The Burn of Mar, behind Conic Hill.

National Trust for Scotland rangers said livestock upstream may have contaminated the water and warned that boiling is safer than trusting filters alone. That advice matters because the burns and rivers along the route can appear clear while still carrying contamination that portable filters may not remove completely. The pattern of illness suggests the risk is not limited to a single one-off pool or crossing point.

The West Highland Way stretches 96 miles from Milngavie in East Dunbartonshire to Fort William in the Highlands. Opened in 1980 as Scotland’s first designated long-distance route, it now draws about 120,000 people a year, with around 36,000 walking the full trail. Those numbers make the safety message more than a local warning: this is a major public route where water advice affects tens of thousands of people each season.

The latest rescue has sharpened attention on how clearly hazards are being signposted around Balmaha, Rowardennan and Conic Hill, where walkers are most likely to top up from burns. For a trail that markets Scotland’s long-distance walking experience, the basic instruction is increasingly simple: do not assume clear water is safe, do not assume a filter is enough, and treat untreated natural water as a contamination risk unless it has been boiled or otherwise made safe.