NASCLA Commercial General Building Contractor Exam — All Questions

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1 questions

Mechanical & Plumbing

A commercial building's potable water system connects to an irrigation system. What device prevents contaminated water from being drawn back into the potable supply?

a.A cleanout
b.A floor drain
c.A backflow preventer✓
d.A pressure-reducing valve

A backflow preventer stops non-potable or contaminated water from siphoning or being pushed back into the potable water supply when pressure drops or reverses. Cross-connections like irrigation tie-ins are exactly where codes require backflow protection.Plumbing: backflow prevention

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