3.2.6 Gravity Mains
This section details the specifications for the sewer gravity mains and access chambers.
Zone 1 — Bungalows 17–59
- Pipe: DN150 PVC gravity main running parallel to the access road, discharging to SPS1 (SSP1) septic tank
| Chamber | CCTV | Location |
|---|---|---|
| Access Chamber 1 | MH C | Next to Bungalow / Unit 17 |
| Access Chamber 2 | MH A | Behind Unit 40 (common area between Units 39 and 40) |
| Access Chamber 3 | MH B | Common area between Bungalows / Units 55 and 56 |
Known Issues
- Groundwater Ingress: Observed through joins in the access chamber nearest SSP1
- Sealing: Gaps present between lids and riser pipes in both chambers
- Main infiltration (CCTV 6 March 2026): Gushing infiltration A → C at 20.4 m (Unit 39) and running infiltration B → A at 0.8 m (Unit 40). Unit 41 branch inflow at 9.20 m is under investigation. Pipe barrel structural grade 1.
East-side Priority 1 repairs and the Unit 41 investigation are targeted for September 2026. See 5. East Side Septic Main Repair.
Zone 2 — Bungalows 1–16
- Pipe: Gravity sewer main to SPS2 (SSP2) STEP tank
- Note: Previously fed a distribution box and septic tanks (now removed and replaced by the 22 kL STEP tank)
Zone 3 — Bungalows 65–66, 75–80
- Pipe: Gravity sewer mains to SSP4 and SSP5 septic systems, then to SPS3 (SSP3) via 32 mm pipeline
Version Control
| Version | Date | Description |
|---|---|---|
| 1.0 | 2025-10-06 | Initial Release |
| 2.0 | 2026-06-22 | Updated Zone 2 for STEP tank; added Zone 3 reference |
| 2.1 | 2026-08-31 | Linked 2026 gravity sewer main repair |
| 2.2 | 2026-08-31 | MH A–C labels and DHE CCTV Priority 1 defects |
Next Review Date: 2026-12-22