Chapter 11 Quiz: Sewer Lines and Septic Systems

Multiple Choice

1. The sewer lateral — the pipe connecting your house to the municipal sewer main — is:

a) Owned and maintained by the municipal water utility from the property line to the main b) The homeowner's responsibility from the house to the sewer main, regardless of whether it crosses public property c) Maintained by the city up to the connection at the sewer main, and by the homeowner for interior section only d) A shared responsibility between homeowner and utility, with costs split 50/50

2. A home built in 1958 most likely has what type of sewer lateral material?

a) PVC plastic, the standard material since the 1950s b) Clay tile pipe with bell-and-spigot joints c) PEX flexible tubing d) CPVC rigid plastic

3. During a sewer camera inspection, a section of pipe appears deformed and non-circular — the pipe walls have buckled inward, leaving only a partial opening. This is most consistent with:

a) Heavy mineral scale buildup in a cast iron pipe b) Root intrusion in a clay tile joint c) Orangeburg pipe that has lost structural integrity and is collapsing d) Offset joints caused by soil settlement

4. In a conventional septic system, what is the function of the outlet baffle in the septic tank?

a) It prevents backflow of solids from the drain field into the tank b) It directs incoming waste downward into the tank's liquid zone c) It prevents floating scum from exiting with the effluent, allowing only the clarified liquid middle layer to flow to the drain field d) It regulates the flow rate of effluent to the distribution box

5. How often should a 1,000-gallon septic tank serving a household of four people typically be pumped?

a) Every 1–2 years b) Every 3–4 years c) Every 8–10 years d) Only when problems appear

6. Which of the following is the MOST harmful item to regularly flush into a septic system?

a) Toilet paper (single-ply) b) Small amounts of vegetable scraps from a garbage disposal c) "Flushable" wipes d) Occasional household cleaning products in normal use

7. Trenchless sewer repair via CIPP (Cured-in-Place Pipe) lining is NOT appropriate for which of the following situations?

a) A clay tile lateral with minor root intrusion at joints b) A cast iron lateral with interior corrosion but structurally intact walls c) An Orangeburg lateral that has lost its structural integrity and is collapsing d) A lateral with minor ground movement at a single joint

8. The perc test (percolation test) performed when designing a septic system measures:

a) The number of gallons of effluent the tank can hold b) The rate at which water is absorbed by the native soil, which determines drain field size requirements c) The level of bacterial activity in the tank d) The slope of the drain field trench for proper effluent flow

9. An upwelling of wet, odorous liquid in the soil over the drain field area during dry weather most likely indicates:

a) A normal condition caused by heavy rainfall from recent weeks b) Drain field saturation or failure — effluent is no longer being absorbed and is surfacing c) A high water table — normal for certain seasons d) The distribution box has overflowed and needs to be emptied

10. When is it appropriate to plant trees near a drain field?

a) Small ornamental trees are acceptable if planted within 15 feet of the field edge b) Any trees are acceptable as long as they are not directly over the distribution pipes c) Trees should be kept at a minimum of 30–50 feet from the drain field edge — and more for aggressive species like willow and poplar d) Trees actually help drain fields by uptaking effluent through their roots and are encouraged

Short Answer

11. Explain why the sewer lateral is the homeowner's responsibility and describe two common failure modes in a clay tile lateral older than 50 years.

12. A homeowner describes "cross-drain backup" — when they run the washing machine, water bubbles up in the toilet, and when they flush the toilet, the shower drain gurgles. What does this symptom indicate, and what should the homeowner do immediately?

13. Compare CIPP pipe lining and pipe bursting as trenchless sewer repair methods. For what type of pipe condition is each most appropriate?

14. Describe the three layers that form inside a septic tank during normal operation, and explain why the sludge layer makes periodic pumping necessary even when the system seems to be working normally.

15. A homeowner on septic wants to understand whether their drain field is healthy. Describe three observable conditions — two you can detect outdoors and one you might notice inside the house — that would suggest the field is functioning normally versus beginning to fail.

Answer Key

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

Short Answer Guidance:

11. The lateral is private infrastructure that runs on (and sometimes under) the homeowner's property. The municipal utility owns and maintains the sewer main under the street; the homeowner owns everything from the house to the main, including any portion under the sidewalk or street up to the connection point. Two clay tile failure modes: (1) Root intrusion — tree roots enter through loosened bell-and-spigot joints, grow into the pipe interior, and eventually cause blockages and joint failure. (2) Pipe offset/belly — soil settlement or freeze-thaw cycles cause individual pipe segments to shift, creating step-joints that catch debris and low spots where solids accumulate rather than flowing toward the main.

12. Cross-drain backup is a nearly definitive sign of a main drain line or sewer lateral obstruction — all drains on the lower part of the drainage system share the main stack and lateral, so a blockage downstream of where they converge causes water and air to find alternate paths. The homeowner should immediately: stop using all water-generating appliances, check that no more water is being sent into the system, and call a plumber for emergency service. This is not something to try to resolve with a hand auger — it requires either a power drain auger or camera inspection to locate and clear the blockage.

13. CIPP lining: a flexible tube saturated with resin is inserted into the existing pipe and cured, creating a new pipe within the old one. Best for pipes with intact enough walls to bond to — cracked clay, corroded cast iron, joint gaps, root-infiltrated pipe where walls remain structurally sound. Reduces interior diameter slightly. Cannot correct bellies or severe alignment problems. Pipe bursting: a bursting head fractures the old pipe outward as it's pulled through, while simultaneously pulling in a new pipe behind it. Best for pipes that are too structurally compromised to line (nothing for a liner to bond to), and appropriate for clay and cast iron (both fracture cleanly). Not effective for Orangeburg (too soft — it compresses instead of breaking) and doesn't work well in curves.

14. Three layers: (1) Scum layer — fats, oils, and light materials float to the surface. (2) Effluent (liquid layer) — the clarified liquid middle zone that flows to the drain field. (3) Sludge layer — heavy solids and inorganic material that sink and accumulate on the bottom. Anaerobic bacteria digest organic solids in the sludge, reducing their volume — but this digestion doesn't eliminate them entirely. The sludge layer grows slowly over time. When it accumulates enough, it reduces the tank's liquid volume, shortens the retention time of effluent (meaning less treatment before it reaches the field), and eventually allows sludge and scum to overflow into the drain field, clogging the distribution pipes. Pumping removes accumulated sludge and scum, resetting the system.

15. Healthy drain field indicators: (1) Outdoor: lawn over the drain field area is normal in appearance relative to surrounding grass — not unusually lush or green in dry periods, not wet or soggy, no odor. (2) Outdoor: no ponding or surface wetness visible over the trench lines even after heavy rain (some temporary wet after heavy rain can be normal — chronic wetness is not). (3) Indoor: drains throughout the house flow at normal speed with no gurgling or backup at multiple fixtures — which would indicate the field is saturated and effluent is backing up rather than being absorbed. Normal indoor drain behavior suggests the field is accepting effluent at the design rate.