Theresa Bellish

Senior Director

Water Systems

Theresa Bellish has over 25 years of experience in the testing, inspection and certification industry with a concentration in drinking water treatment chemicals, distribution system components, recreational water products, onsite wastewater treatment systems, sustainability, biosafety cabinetry and electrical safety services. She joined NSF in 2000 and has held several leadership positions, including roles as Business Unit Manager, Operations Manager, General Manager and Senior Managing Director. She has led sales, project management and technical teams.

Previously, Bellish served as Senior Certification Project Manager, providing her technical knowledge and product management skills to help with business operations. Additionally, she served as a microbiological control analyst for a pharmaceutical company, helping test, monitor and validate laboratory analyses.

Bellish is a member of AWWA, PHTA & NOWRA.

Her areas of expertise include:

Strategic planning
Business development
Water treatment and quality
Team Management & Leadership
Operations
Environmental awareness and compliance.