--- title: "Detail estimate report for sewerage project" subject: "Estimating and Costing" chapter: 5 key: "semester_7/estimating_and_costing:estimate-report-sewerage" source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/estimate-report-sewerage site: BCT Engineering --- # Detail estimate report for sewerage project Estimating and Costing · Chapter 5: Project Estimate - Asked in: 2082 Baisakh, 6 marks; 2080 Bhadra, 6 marks (asked 2 times) - Video: [How to Prepare Estimation of Sewer Line | QSC-[HINDI]](https://www.youtube.com/watch?v=2Mc75o-yKR4) — Learn Civil Tech & Tricks - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/estimate-report-sewerage - Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-5 ## Question Explain the different data required and sub-heads of sanitary works to be included in the detailed estimation report for installation of sewer in a city (prepare a detailed estimate report for a small sewerage project). ## Short answer Sewerage estimate needs survey, population/design flow, hydraulic design, soil/groundwater, drawings/specs, rates, land and environmental data. Sub-heads include preliminary, land, trench excavation, pipes, manholes, house connections, pumping, treatment, road restoration, contingencies and VAT. The specimen scheme totals NPR 25,042,608. ## Answer A sewerage project collects and carries the wastewater of a town through a network of pipes to a treatment unit and a safe disposal point. Its detailed estimate is prepared after the survey and design are complete. #### Data required 1. **Survey:** topographic map, road network, levels and slopes, location of outfall and treatment site. 2. **Population and flow data:** present and design-year population (usually 20 years), per-capita water supply (typically 100–135 lpcd in towns), sewage flow = 80% of water supply, peak factor. 3. **Hydraulic design:** pipe diameters, gradients (self-cleansing velocity not below 0.6–0.75 m/s, not above about 3 m/s), manhole spacing (30–50 m), depth of cover. 4. **Soil and groundwater data** for trench excavation, shoring and dewatering. 5. **Drawings and specifications:** layout, longitudinal sections, manhole details, treatment plant design. 6. **Rates:** District Rates for excavation, pipes, concrete, brickwork, labour, transport; land and wayleave data; environmental and social data. #### Sub-heads of sanitary works - Preliminary: survey, investigation, design, supervision. - Land and compensation (treatment site, wayleave). - Excavation, shoring, dewatering, bedding and backfilling of trenches. - Supply, laying, jointing and testing of sewer pipes (trunk, main, lateral). - Manholes, drop manholes, inspection chambers, flushing and ventilating arrangements. - House connections and gully traps. - Pumping station (if gravity flow is not possible) and electromechanical works. - Treatment plant (screen, grit chamber, sedimentation, stabilisation pond or similar) and outfall. - Restoration of road surface, miscellaneous and contingencies, supervision, VAT. #### Specimen detailed estimate report for a small sewerage scheme Report headings: (1) introduction and project description, (2) design basis, (3) abstract of cost, (4) detailed quantities and rate analysis, (5) specifications, (6) drawings, (7) work programme. Illustrative abstract of cost (quantities and rates are assumed): | S.N. | Item | Qty | Unit | Rate (NPR) | Amount (NPR) | |---|---|---:|---|---:|---:| | 1 | Survey, design and investigation (lump) | 1 | LS | 350,000 | 350,000 | | 2 | Excavation in trenches | 3,200 | m³ | 700 | 2,240,000 | | 3 | 300 mm dia. RCC NP2 sewer pipe, laid and jointed | 1,500 | m | 3,800 | 5,700,000 | | 4 | 200 mm dia. uPVC sewer pipe, laid and jointed | 1,200 | m | 2,200 | 2,640,000 | | 5 | Brick manholes (1.2 m dia., about 1.8 m deep) | 45 | no | 38,000 | 1,710,000 | | 6 | House connections | 120 | no | 6,500 | 780,000 | | 7 | Backfilling and compaction | 2,800 | m³ | 350 | 980,000 | | 8 | Road and pavement restoration | 900 | m² | 1,800 | 1,620,000 | | 9 | Waste stabilisation pond / treatment unit (lump) | 1 | LS | 4,500,000 | 4,500,000 | | | **Sub-total** | | | | **20,520,000** | | | Physical contingency 5% | | | | 1,026,000 | | | Supervision and administration 3% | | | | 615,600 | | | VAT 13% | | | | 2,881,008 | | | **Total project cost** | | | | **25,042,608** | **Total estimated cost = NPR 25,042,608.** ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What limits are given for velocity in a sewer? A. Not below 3 m/s and not above 10 m/s B. Not below 0.1 m/s and not above 0.3 m/s C. Not below 0.6-0.75 m/s and not above about 3 m/s D. Not below 1.5 m/s and not above 6 m/s Answer: C. Low velocity causes deposits; very high velocity erodes the pipe. (Key point: Self-cleansing velocity) 2. How is sewage flow related to water supply? A. Sewage flow equals 100% of water supply plus infiltration B. Sewage flow is 20% of water supply C. Sewage flow is double the water supply D. Sewage flow is taken as 80% of the water supply Answer: D. Part of the supplied water is lost in use, so 80% reaches the sewer. (Key point: Sewage flow) 3. Which item belongs to sanitary-work sub-heads? A. Trench excavation, pipe laying, manholes, house connections and restoration of road surface B. Only the treatment plant C. Only survey and design D. Gates and hoists of a weir Answer: A. These make up the sewer network works. (Key point: Sub-heads) 4. How is the total project cost obtained in the abstract? A. Sub-total plus only 13% VAT B. Sub-total plus 5% contingency, 3% supervision and 13% VAT C. Sub-total minus contingency D. Sub-total multiplied by 5% Answer: B. 20,520,000 + 1,026,000 + 615,600 + 2,881,008 = 25,042,608. 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