Community Water System
Why This Matters
A single person can haul water from a stream. Thirty people cannot — not without spending half their productive hours carrying buckets. A shared water system is the single biggest quality-of-life upgrade for a small community, and it frees up labor for everything else.
Calculating Demand
Start with the numbers. Each person needs a minimum of 20 liters per day for drinking, cooking, and basic hygiene. For a comfortable community with laundry and garden irrigation, plan for 50-80 liters per person per day. Livestock adds significantly: a cow drinks 50-80 L/day, a goat 5-10 L/day, chickens about 0.5 L each.
For a group of 20 people with a small garden and some livestock, you’re looking at roughly 1,500-2,500 liters per day. Design your system for peak demand, not average — there will be days when everyone needs water at once.
Choosing a Source
In order of preference:
- Protected spring — most reliable, cleanest, lowest maintenance
- Stream or river — abundant but requires filtration and is vulnerable to upstream contamination
- Deep well with hand pump — reliable year-round if aquifer is good
- Rainwater collection — supplement only in most climates; primary source only in high-rainfall areas
Whatever your source, measure its dry-season flow before committing. A spring that produces 5 liters/minute in April might drop to 0.5 L/min in August. Your system must work in the worst month, not the best.
Tip
To measure flow rate: dam the source temporarily, direct all water into a pipe, and time how long it takes to fill a known container. A 20-liter bucket filling in 60 seconds = 0.33 L/min. Do this weekly for at least a full season before building permanent infrastructure.
Gravity-Fed System Design
Gravity is free and never breaks down. If your source is at least 10 meters higher than your settlement, a gravity-fed system is almost always the right choice.
Head calculation: Every 10 meters of vertical drop gives you approximately 1 bar (14.5 psi) of pressure. You need at least 0.5 bar (5m head) at your lowest distribution point for water to flow reliably from a tap.
Subtract friction losses: for every 100m of horizontal pipe run, subtract roughly 1-3m of head (depending on pipe diameter and flow rate). Smaller pipes = more friction. Use the largest diameter pipe you can get for the main line — 50mm (2”) minimum for serving 10+ people.
Break pressure tanks: If your source is more than 60m above your distribution point, install a break pressure tank partway down. This is simply a small open tank (100-200L) that interrupts the pipe run and resets the pressure to zero. Without it, excessive pressure will blow joints and fittings.
Pipe Selection
| Material | Pros | Cons | Best For |
|---|---|---|---|
| HDPE (black poly) | Flexible, UV-resistant, easy to join with barbed fittings | Requires clamps, can kink | Main lines, buried runs |
| PVC | Cheap, rigid, solvent-welded joints are strong | Brittle in cold, UV-degrades above ground | Distribution networks |
| Bamboo | Free, available everywhere tropical | Rots in 2-5 years, leaks at joints | Temporary systems |
| Galvanized steel | Very strong, long-lasting | Heavy, expensive, rusts internally over decades | High-pressure sections |
For most community systems: HDPE for the main line from source to storage tank, PVC for distribution from tank to standpipes. Bury all pipes at least 30cm deep to protect from UV, physical damage, and frost.
Warning
Never use lead solder on any water pipe joint. Never use pipe salvaged from unknown industrial applications — it may be contaminated with heavy metals or chemicals.
Distribution Points
Don’t pipe water to every individual dwelling unless you have abundant supply and good pressure. Start with communal standpipes — one for every 5-8 households, within 200m of each home.
Each standpipe needs:
- A tap (gate valve or ball valve)
- A concrete drainage pad (1.5m x 1.5m, sloped away from the tap) to prevent mud
- A drainage channel leading away from the collection area
- A soakaway pit at the end of the drain
Seasonal Considerations
Dry season: If your spring flow drops below demand, you need either a larger storage tank to buffer overnight, a backup source (well, rainwater), or demand reduction rules (rationing schedules).
Freezing climates: Bury pipes below the frost line (varies by region: 0.5m in mild areas, 1.5m+ in cold climates). Drain exposed sections before winter. Insulate above-ground tanks with straw bales or earth berms.
Rainy season: Protect your intake from flooding and sediment. A simple settling basin upstream of your intake catches debris and silt before it enters the pipe.
Governance
A water system without a maintenance plan will fail within 2 years. Assign a water committee of at least 3 people. Their responsibilities:
- Weekly inspection of intake, tank, and all standpipes
- Monthly flushing of the system (open the lowest valve and let water run for 5 minutes)
- Keeping a small stock of spare fittings, pipe, and tools
- Enforcing rules: no washing clothes at the standpipe, no connecting unauthorized branch lines, no leaving taps running
Common Mistakes
| Mistake | Consequence | Prevention |
|---|---|---|
| Undersizing pipes | Low flow, long wait times | Use minimum 32mm for branch lines, 50mm for mains |
| No storage tank | System fails when source flow < peak demand | Install tank holding at least 1 day’s supply |
| Exposed pipes above ground | UV damage, physical damage, freezing | Bury all pipes or protect with earth cover |
| No drainage at standpipes | Mud pit, mosquito breeding, contamination | Concrete pad + drainage channel + soakaway |
| Building before measuring dry-season flow | System runs dry in summer | Monitor source flow for at least one full season |
What’s Next
- Water Distribution — detailed pipe network design
- Water Treatment at Scale — making your supply safe to drink
- Cisterns and Rainwater Storage — buffering supply with large storage