CHAPTER 3

Water Demand, LPCD Standards, and Peak Factors

Q: What is the design LPCD for urban areas?

135 lpcd for urban areas with underground sewerage; 70 lpcd without sewerage. Metros (Delhi, Mumbai, Bangalore, Hyderabad, Chennai, Kolkata) justify 150-200 lpcd due to higher standard of living.

Q: What is rural LPCD per JJM?

55 lpcd per BIS 1172:2012 (adopted by Jal Jeevan Mission). Older CPHEEO 40 lpcd figure is legacy — JJM schemes design for 55 lpcd through functional household tap connections (FHTC).

Q: What is maximum hourly demand factor?

Maximum hourly demand = 2.7 × average hourly demand, or equivalently 1.5 × maximum daily demand / 24. This governs distribution system design. For 24×7 supply, peak factor reduces to 1.3-1.8.

Q: How do I calculate fire demand?

Use Kuichling: Q (L/min) = 3182 × √P, or Freeman: Q = 1136 × (P/5 + 10), where P = population in thousands. Take higher value. For 100,000 population: ~32,000 L/min.

Q: What is UFW (Unaccounted-For-Water)?

Water produced but not billed — due to physical leakage, theft, unauthorized connections, metering errors. CPHEEO design allowance 15%; Indian urban utilities actually 35-45%. AMRUT/JJM target < 20%.

Q: What peak factor for source and transmission?

Source intake and raw water main: 1.0 (continuous 24-hr operation). Treatment plant: 1.1-1.2. Clear water pumping: 1.5. Distribution system: 2.5-3.0 (intermittent) or 1.3-1.8 (24×7).

Water Demand & LPCD

Specifies per-capita water demand (LPCD) for urban and rural settings, category-wise demand (domestic, industrial, commercial, institutional, firefighting, losses), and peak factors used to design source works, treatment plants, transmission mains, and distribution systems.

💧 Water Demand & LPCDManual on Water Supply and Treatment3rd Edition (1999) with 2024 revision updates

Key formulas

Average Daily Demand (m³/day) = Population × LPCD / 1000
Maximum Daily Demand = 1.8 × Average Daily Demand (for source, raw water main).
Maximum Hourly Demand = 2.7 × Average Hourly Demand = 1.5 × Maximum Daily / 24 (for distribution).
Fire Demand (Kuichling's formula): Q (L/min) = 3182 × √P, where P = population in thousands.
Fire Demand (Freeman's formula): Q (L/min) = 1136 × (P/5 + 10), where P = population in thousands.
Unaccounted-for-Water (UFW) allowance: add 15% of demand for losses, leakage, unauthorized use.

Key values & thresholds

urban with sewerage lpcd: 135
urban without sewerage lpcd: 70
rural piped lpcd: 55 (BIS 1172:2012) / 40 (CPHEEO legacy)
rural stand post lpcd: 40
metropolitan cities lpcd: 150-200 (Delhi, Mumbai revised)
domestic component pct: 55-70% of total
industrial component pct: 10-20%
commercial component pct: 5-15%
institutional component pct: 5-10%
firefighting component pct: 1-5%
ufw losses allowance pct: 15
max day to avg day factor: 1.8
max hour to avg hour factor: 2.7
peak factor distribution system: 2.5-3.0
peak factor raw water main: 1.0

Clause-level requirements

Urban design LPCD of 135 applies when full underground sewerage exists; reduced to 70 lpcd where sewerage is absent (septic tanks).
Metropolitan cities (population > 40 lakh) justify higher LPCD (150-200) due to higher standard of living and larger per-capita commercial/institutional water use.
Rural LPCD for piped supply is 55 per BIS 1172:2012, superseding the older CPHEEO figure of 40 lpcd. JJM (Jal Jeevan Mission) uses 55 lpcd design standard.
Peak factors: source and raw water main at 1.0 (continuous 24-hr operation); treatment plant at 1.1-1.2 (allow for shutdowns); clear water pumping at 1.5; distribution system at 2.5-3.0 to meet peak hour demand.
Fire demand calculation via Kuichling or Freeman formula; provide dedicated fire hydrant system in urban areas with population > 50,000.
UFW losses (leakage, metering error, unauthorized connections, theft) — target < 15% but Indian urban utilities average 35-45%. Allow 15% for design; reduce through active leak detection.

Practitioner notes — what goes wrong in the field

For metros (Delhi, Mumbai, Chennai, Kolkata, Bangalore, Hyderabad), design for 150-200 lpcd due to higher standard of living. Mumbai current supply 240 lpcd (highest in India).
Tier-2 cities (Lucknow, Indore, Surat, Bhubaneswar) operate at 100-135 lpcd. Design for 135 lpcd with growth.
Rural LPCD — JJM insists on 55 lpcd through household taps (FHTC). Older 40 lpcd via hand pumps and stand-posts no longer acceptable.
Industrial demand: for water-intensive (paper, pulp, chemicals, power plant cooling, thermal) calculate specifically — can exceed 5000 l/worker/day. For light industry 100 l/worker/day adequate.
Commercial: hotels 450 l/bed-day, restaurants 70 l/meal, offices 45 l/person-day, cinema 15 l/seat-day, market 2.5 l/m²-day.
Institutional: schools 25 l/student-day day schools, 135 l/student-day residential; hospitals 450 l/bed-day (general), 900 l/bed-day (specialized).
Fire demand: calculate both formulae and use higher. Example: 100,000 population → Kuichling 3182 × √100 = 31,820 L/min ≈ 2000 m³/hr peak for 2-4 hours.
Fire storage: 50% of fire demand × 4 hours for hydrant system + dedicated fire reservoir. In commercial areas with high-rise buildings (Mumbai, Gurgaon, Bangalore CBD), fire demand can exceed 5000 L/min per block.
UFW reduction: Bangalore BWSSB reduced from 49% (2006) to 35% (2022) through district metering and pressure management; saved equivalent of 250 MLD source capacity.
Peak factor 2.5-3.0 for distribution system reflects sudden morning/evening demand spikes. Pipe sizing is governed by peak hour, not average.
24×7 supply (JJM target, AMRUT): reduces peak factor to 1.3-1.8 as demand spreads throughout day. Intermittent supply (2-6 hrs/day currently) has peak factor 4-5.

FAQs

What is the design LPCD for urban areas?

135 lpcd for urban areas with underground sewerage; 70 lpcd without sewerage. Metros (Delhi, Mumbai, Bangalore, Hyderabad, Chennai, Kolkata) justify 150-200 lpcd due to higher standard of living.

What is rural LPCD per JJM?

55 lpcd per BIS 1172:2012 (adopted by Jal Jeevan Mission). Older CPHEEO 40 lpcd figure is legacy — JJM schemes design for 55 lpcd through functional household tap connections (FHTC).

What is maximum hourly demand factor?

Maximum hourly demand = 2.7 × average hourly demand, or equivalently 1.5 × maximum daily demand / 24. This governs distribution system design. For 24×7 supply, peak factor reduces to 1.3-1.8.

How do I calculate fire demand?

Use Kuichling: Q (L/min) = 3182 × √P, or Freeman: Q = 1136 × (P/5 + 10), where P = population in thousands. Take higher value. For 100,000 population: ~32,000 L/min.

What is UFW (Unaccounted-For-Water)?

Water produced but not billed — due to physical leakage, theft, unauthorized connections, metering errors. CPHEEO design allowance 15%; Indian urban utilities actually 35-45%. AMRUT/JJM target < 20%.

What peak factor for source and transmission?

Source intake and raw water main: 1.0 (continuous 24-hr operation). Treatment plant: 1.1-1.2. Clear water pumping: 1.5. Distribution system: 2.5-3.0 (intermittent) or 1.3-1.8 (24×7).

Calculator

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Water Demand, LPCD, and Peak Factors

↓ Download Excel

Compute average daily, max daily, peak hour, and design flow for the 30-year horizon. Includes fire demand (Kuichling) and UFW allowance per CPHEEO Chapter 3.

Inputs

Design populationpersons

Per-capita supplyLPCD

135 urban+sewer, 70 urban, 55 rural (JJM/BIS 1172:2012)

Max day / avg day factor×

Max hour / avg hour factor×

2.5-3.0 intermittent; 1.3-1.8 for 24×7 supply

UFW (NRW) allowance%

Outputs

Average daily demand

13,500m³/day

Q = Population × LPCD / 1000

Average daily demand

13.50MLD

Maximum daily demand

24,300m³/day

Q_max_day = factor × Q_avg

↪ For source, raw-water main sizing

Maximum hourly demand

1,518.75m³/hr

Q_peak_hr = pfHr × (Q_avg / 24)

↪ For distribution pipe sizing

Fire demand (Kuichling)

31,820L/min

Q_fire = 3182 × √(P/1000)

Design flow (distribution, with UFW + Fire)

35,581.8m³/day

Q_design = Q_max_day × (1 + UFW%) + Q_fire × 4 hr

CPHEEO Reference Values

LPCD urban+sewer135

LPCD urban no-sewer70

LPCD rural (JJM)55

Max-day factor1.8

Peak-hour factor2.5–3.0 (intermittent), 1.3–1.8 (24×7)

UFW design allowance15% (AMRUT/JJM target <20% actual)

Download the Excel version to keep a local copy with live formulas — change inputs in the sheet and outputs recompute automatically.

Cross-references

IS 1172:2012CPHEEO WS Chapter 1NFPA Fire ProtectionAMRUT Mission