Hydro Diagnostics raises SEK 3.4M seed for rapid on-site water bacteria testing

Hydro Diagnostics Secures Seed Funding

Hydro Diagnostics, a Stockholm-based biotech startup, has raised SEK 3.4 million in seed funding. The round was backed by investors Carl Starfelt and Jesper Karlström.

What the Company Does

Hydro Diagnostics develops rapid, on-site testing for bacteria in water. Its kit follows a pregnancy-test-style format: a concentration filter paired with a lateral-flow test cassette that is read by an AI-powered mobile app.

The system detects organisms such as Legionella and E. coli in about 30 minutes. By comparison, conventional lab analysis takes 10 to 14 days.

Origins and Team

The company was founded by Erik Wåhlin and Kevin Siu in the wake of the COVID-19 pandemic.

Customers and Market

Hydro Diagnostics primarily serves property owners and managers responsible for water safety under EU directives. The company sells test kits on a recurring basis, positioning itself around ongoing compliance needs rather than one-off testing.

Operations

Production is handled by a partner in Belgium.

Deal Summary

• Company: Hydro Diagnostics
• Headquarters: Stockholm
• Stage: Seed
• Amount raised: SEK 3,400,000
• Funding date: October 1, 2026
• Investors: Carl Starfelt, Jesper Karlström

Why It Matters

The gap between a 30-minute on-site result and a 10-to-14-day lab turnaround is the core of Hydro Diagnostics' proposition. For property owners and managers operating under EU water safety directives, faster detection can mean faster response to contamination events. The recurring kit model also creates a repeat-revenue profile tied to routine compliance testing.

With seed funding in place, the company is positioned to scale a product that combines hardware — the concentration filter and lateral-flow cassette — with software in the form of its AI-powered mobile app.