Chapter 10 Quiz: Common Plumbing Problems

Multiple Choice

1. You suspect a hidden water leak. You turn off all water in the house and go to the water meter. The leak indicator is spinning slowly. You then go inside, close the main house shutoff, and return to the meter — the indicator has stopped spinning. This tells you:

a) The leak is between the meter and the main house shutoff (in the service line) b) The leak is inside the house, between the shutoff and the fixtures c) The meter itself is faulty d) The leak was a phantom and has self-corrected

2. Chemical drain cleaners are generally not recommended for older metal pipes because:

a) They react with metal to create toxic gases that poison groundwater b) They generate exothermic heat that can soften plastic and worsen corrosion damage in older metal pipes c) They dissolve the rubber washers in shutoff valves when they flow past d) They are only effective on grease clogs, not hair clogs

3. Water pressure in a home should ideally be maintained between:

a) 20–40 PSI b) 45–70 PSI c) 80–100 PSI d) 100–120 PSI

4. A homeowner hears a loud thump from inside the wall every time the washing machine stops filling. This is most accurately described as:

a) A failing fill valve in the washing machine b) A water hammer caused by the sudden closure of the machine's solenoid valve c) Thermal expansion in the supply pipes caused by hot water d) A loose supply line that is vibrating against the wall

5. What is the recommended action for thawing a frozen pipe?

a) Apply an open-flame torch to the pipe, moving quickly to prevent concentration of heat b) Wrap the pipe in towels soaked in boiling water to maximize heat transfer speed c) Open the downstream faucet first, then apply gentle heat from the faucet side toward the frozen section d) Close the downstream faucet completely, then apply a heat gun on maximum setting to break up the ice

6. The LEAST effective and potentially most dangerous method for clearing a drain clog is:

a) A plunger on a completely blocked drain b) Chemical drain cleaner poured into a completely blocked drain c) A hand auger inserted into the drain d) Boiling water (for metal pipe and CPVC)

7. Multiple drains throughout the house are backing up simultaneously when any fixture is used. The most likely explanation is:

a) Low water pressure causing siphoning back through multiple drain traps b) A failed expansion tank on the water heater c) A main drain line or sewer lateral obstruction affecting all downstream fixtures d) Multiple simultaneous flapper failures in several toilets

8. A pressure reducing valve (PRV) is typically located:

a) At the water heater cold-water inlet b) Inside the water meter housing at the street c) At the main entry point where the supply line enters the house d) On the main water supply line in the municipal distribution system

9. Pipes in which location are MOST vulnerable to freezing?

a) Interior walls of a well-insulated home b) Below the basement slab in conditioned space c) Exterior walls or in unheated spaces such as crawl spaces and garages d) Adjacent to the water heater in a utility room

10. When should you cut electrical power to an area affected by a water leak?

a) Only after the plumber has assessed the situation b) Never — water and electrical panels should not be touched by homeowners c) Immediately if water is near electrical outlets, switches, or wiring — before attempting any other action in that area d) Only if the water has been flowing for more than one hour

Short Answer

11. Describe the complete water meter leak test procedure, including what it tells you when the meter stops moving after you close the main house shutoff versus when it keeps moving.

12. Rank the following drain clog solutions from least to most invasive and expensive, and identify which is best suited for a hair clog in a bathroom sink: chemical drain cleaner, Zip-It tool, plunger, hand auger, hydro-jetting.

13. A homeowner in a northern climate is leaving their house for a two-week vacation in January. What are the three most important actions they should take to prevent frozen pipes while away?

14. What causes water hammer and what are two different solutions — one the homeowner can install themselves and one that addresses the root cause of high pressure?

15. You discover a slow leak at a compression coupling on an accessible copper supply pipe in your basement. You have time to arrange a proper repair next week, but the drip needs to be stopped today. Describe a temporary repair approach and explain why it is not a permanent solution.

Answer Key

Multiple Choice: 1. b 2. b 3. b 4. b 5. c 6. b 7. c 8. c 9. c 10. c

Short Answer Guidance:

11. Water meter leak test: (1) Ensure zero water use in house — all fixtures off, no running toilets, no appliances. (2) Observe the leak indicator at the meter. If it moves: (3) close the main house shutoff and recheck the meter. If the meter stops: leak is inside the house between shutoff and fixtures — likely a dripping fixture, running toilet, or indoor pipe leak. If the meter is still moving even with the shutoff closed: the leak is in the service line between the meter and the shutoff, which is the homeowner's responsibility to repair. If the indicator wasn't moving: no active leak — good baseline established.

12. Least to most invasive: Zip-It tool (physical removal, free, seconds) → Plunger (physical pressure, $10, minutes) → Hand auger (mechanical, $25, 15–30 minutes) → Chemical drain cleaner (chemical, $8–$15, hours — with caveats about pipe damage) → Hydro-jetting (professional, $300–$600). For a hair clog in a bathroom sink: the Zip-It tool first — hair clogs are physical and in the trap area, exactly what the Zip-It is designed for. Chemical cleaners are among the worst choices for hair (they dissolve the surface but not the core) and should not be used in this application.

13. (1) Set the thermostat to a minimum of 55–60°F — never let the house go below this. (2) Shut off and drain the irrigation system. (3) Open cabinet doors under sinks on exterior walls before leaving. Bonus actions: let a trusted person know so they can check on the house; know where the main shutoff is and confirm it can be closed.

14. Water hammer is caused by the hydraulic shock wave when fast-moving water is suddenly stopped by a rapidly closing valve. Solution 1 (homeowner DIY): Install water hammer arrestors at the supply connections of the offending appliance (washing machine, dishwasher). They contain a gas-charged piston that absorbs the pressure spike. Cost: $15–$40 each. Solution 2 (root cause, pressure): If water pressure is above 80 PSI, adjusting or replacing the PRV to bring pressure into the 50–65 PSI range reduces the energy in the moving water and reduces hammer severity throughout the house.

15. Temporary repair: drain the pipe by closing the supply shutoff and opening a downstream faucet. Dry the pipe thoroughly. Apply a pipe repair clamp — a rubber gasket and metal clamp centered over the leak point, bolts tightened evenly. Or wrap the pipe tightly with self-fusing silicone tape with heavy overlap. Restore pressure slowly and monitor. Not permanent because: a pipe that has developed a leak from corrosion has thinning walls throughout that section; the repair covers one failure point but adjacent metal is equally compromised. A proper repair cuts out the damaged section and replaces it with sound pipe and permanent fittings.