“So one thing I never do is try to start giving remediation or advice before I truly have understood and diagnosed the problem.”
Mentorship and certifications don’t replace experience—but they can accelerate it when paired with the right mindset and a disciplined approach to learning. Nella Fergusson, CWT (District Manager, Southern California, Garratt-Callahan), lays out what “growing up” in industrial water treatment actually looks like: repeated exposure to real problems, strong diagnostic habits, and a willingness to keep learning long after year one.
Learning that keeps you employable
Water treatment evolves. Nella contrasts today’s challenges with what she faced 15 years ago and explains why complacency is the fastest path to getting left behind. She describes water treatment as industry-specific by nature—food processing cooling and commercial real estate operations don’t behave the same, don’t shut down the same way, and can’t be serviced the same way.
Diagnosing before prescribing
Her troubleshooting process starts with questions: the system’s history, what changed, when symptoms appeared, and how critical the impacted use is. She emphasizes water sampling across different times of day and refuses to offer remediation before a proper diagnosis—because misdiagnosis creates extra problems instead of solving the original one.
Career decisions, culture, and the 80/20 risk
Nella shares a candid career detour: leaving Garratt-Callahan for GE Water/Suez, then realizing quickly what she lost—support, resources, and “family”—before returning. She frames many job moves through an 80/20 lens: chasing a missing 20% can cost the 80% that already works, especially when recruiters’ incentives don’t align with yours.
Credentials that signal competence—and protect end users
Nella explains why she pursued the CWT: an industry-agreed benchmark that reflects years of varied problem-solving. She also discusses ASSE 12080 recertification and why correct sampling, shipping, labeling, and interpretation matter—particularly in Legionella and water safety work. Customers may fear testing; she argues the goal is to find risk where maintenance is weak, then build site-specific procedures that facilities can actually sustain with their staffing. Stay engaged, keep learning, and continue scaling up your knowledge!
Timestamps
02:22 – Trace message: CWT prep course + planning for 2026
09:17 – Water You Know with James McDonald
10:48 – Upcoming Events for Water Treatment Professionals
14:49 – Interview with Nella Fergusson, CWT, (District Manager, Southern California, Garratt-Callahan)
16: 27- Ongoing education + how the industry has changed
21:06 – Nella’s troubleshooting approach: history, what changed, sampling, impact, don’t prescribe before diagnosing
31:00 – Nella’s 80/20 rule for deciding whether to leave a company
34:22 – Why she pursued CWT + value of certifications in the industry
40:15 – Getting results immediately + confidence while testing
Connect with Nella Fergusson 
Email: nfergusson@g-c.com
Website: http://www.garrattcallahan.com/
LinkedIn: Nella Fergusson, CWT | LinkedIn
Guest Resources Mentioned
ASSE 12080 Certification – ASSE International
Why ASSE Certifications Matter – Garratt‑Callahan
Impact of Cooling Tower Downtime in Food & Beverage Operations – Aggreko
Scheduling Off‑Peak HVAC Maintenance – Facility Response Group
Scaling UP! H2O Resources Mentioned
AWT (Association of Water Technologies)
Scaling UP! H2O Academy video courses
Water You Know with James McDonald
Question: What is the piece of equipment called that is a heat exchanger placed in the gas passage between the boiler and the stack designed to recover exhaust gas heat into the boiler feedwater?
2025 Events for Water Professionals
Check out our Scaling UP! H2O Events Calendar where we’ve listed every event Water Treaters should be aware of by clicking HERE.
