Hydrant Repair Uncovers a Valve Problem
A crew is replacing a 40-year-old 6-inch hydrant on a residential loop. The gate valve isolating the hydrant will not close fully; the operating nut turns but the valve stem appears to spin without seating. The crew's only option is to close the nearest upstream valve, which also isolates 22 homes and a small clinic. The clinic has dialysis patients and has asked for 24-hour notice of outages. It is 2 p.m. on a Friday. The crew chief wants to proceed immediately to avoid overtime and because 'the hydrant is leaking.' The leak is a slow weep at the bonnet, roughly 2 gpm.
1. Evaluate the crew chief's plan and identify the risks.
Read the worked answer
Proceeding immediately without notice is the wrong call.
Risks:
- Public health: isolating a clinic serving dialysis patients without notice can be dangerous; dialysis requires treated water and advance planning for alternative supply.
- Regulatory/customer relations: the utility's own 24-hour notice commitment would be violated; unplanned outages generate complaints and potential liability.
- Loss of isolation: if the upstream valve also fails or is partially closed, the crew may not be able to complete the repair and could be forced to shut down a larger area at a worse time.
- The leak is minor - a 2 gpm bonnet weep is not an emergency and does not justify skipping notice.
Correct approach: verify the upstream valve operates, notify affected customers (especially the clinic) with the required 24-hour notice, schedule the work for a low-demand period, and stage a plan for the clinic's water needs.
2. The crew discovers the upstream valve is also a 40-year-old gate valve of the same vintage. What should they do before scheduling the outage?
Read the worked answer
Exercise and verify the upstream valve before committing to the outage.
- Operate the valve through its full travel and confirm it seats; if it spins or will not close, the isolation boundary is unreliable.
- Identify the next isolation point upstream and confirm it operates, so a backup boundary exists.
- If no reliable isolation exists, plan for a larger controlled shutdown rather than an uncontrolled one, and coordinate with the clinic and other critical customers.
- Record valve condition in the asset management system; a cluster of failing valves of the same age suggests a valve exercise and replacement program is overdue.
This converts a potential emergency into a planned, safe outage - exactly the judgement the exam tests.
3. Describe the notification and operational steps for the planned outage.
Read the worked answer
- Notify customers at least 24 hours ahead by door hanger, phone, and posted notice; give the clinic direct contact and confirm their contingency plan.
- Coordinate with the clinic on timing and duration; offer bottled water or a temporary connection if needed.
- Schedule during low demand (e.g., overnight or early morning) to minimize impact.
- Stage equipment and parts so the outage is as short as possible.
- Issue a precautionary boil-water notice if pressure drops below the threshold that risks contamination, and follow the utility's rescission procedure after testing.
- Flush and sample after restoration before lifting any notice.
- Document the outage, notifications, and test results.