Complete Cistern and Water Storage Construction: From Pit to Reservoir
⟁ cover painted for this edition — the source module carried no illustrations
Complete Cistern and Water Storage Construction: From Pit to Reservoir
Reliable water storage is essential for survival. This campaign covers cistern types, construction methods, waterproofing, and rainwater collection systems.
Chapter 1: Water Storage Types
Type
Capacity
Material
Difficulty
Durability
Clay-lined pit
100-500 gallons
Excavation + clay lining
Low
Moderate
Ferrocement tank
500-5,000 gallons
Wire mesh + cement mortar
Moderate
Very high
Stone cistern
500-10,000 gallons
Cut or dry-laid stone + plaster
High
Excellent
Brick cistern
500-5,000 gallons
Brick + cement plaster
Moderate-high
Very high
Wooden tank (barrel)
50-500 gallons
Cooperage (staves and hoops)
High
Good
Earthbag tank
200-2,000 gallons
Filled bags + plaster
Low-moderate
Good
Chapter 2: Ferrocement Cistern Construction
Ferrocement cistern (most practical): 1) Excavate hole or build on level ground. 2) Build form: cylindrical (easiest) using plywood or sheet metal. 3) Typical size: 4 feet diameter x 4 feet tall = ~375 gallons. 4) Wrap form with chicken wire (2-3 layers). 5) Add reinforcing wire (tie wire or rebar) vertically and horizontally. 6) Mix mortar: 1 part Portland cement, 3 parts sand, water to thick paste. 7) Plaster mortar onto wire mesh (1/2-3/4 inch thick). 8) Apply from inside and outside simultaneously. 9) Work mortar through mesh (encapsulate all wire). 10) Smooth interior surface (water-tight finish). 11) Cure: keep moist for 7 days minimum. 12) Seal interior with cement slurry or food-grade sealant.
Dimension
Capacity
Wire Mesh
Mortar Volume
Construction Time
3 ft dia x 3 ft tall
~160 gallons
50 sq ft
3 cubic feet
1-2 days
4 ft dia x 4 ft tall
~375 gallons
80 sq ft
5 cubic feet
2-3 days
6 ft dia x 4 ft tall
~845 gallons
120 sq ft
8 cubic feet
3-4 days
6 ft dia x 6 ft tall
~1,270 gallons
150 sq ft
10 cubic feet
4-5 days
Chapter 3: Rainwater Collection
Component
Material
Purpose
Specification
Roof (catchment)
Any impervious roofing
Collect rain
1 inch rain on 1,000 sq ft roof = 623 gallons
Gutters
Wood, metal, or bamboo
Channel water from roof
Slope 1/4 inch per foot toward downspout
Downspout
Pipe or channel
Direct water to cistern
2-4 inch diameter
First flush diverter
Pipe with valve
Discard first dirty water
Diverts first 1 gallon per 100 sq ft of roof
Screen/filter
Wire mesh
Remove leaves, debris
1/4 inch mesh at gutter and inlet
Cistern
Any type above
Store water
Size for local rainfall and usage
Overflow
Pipe at top of cistern
Prevent overfilling
Direct overflow away from foundation
Rainfall calculation: 1) Measure roof area (length x width in feet). 2) Multiply by annual rainfall (inches). 3) Multiply by 0.623 (converts to gallons). 4) Multiply by 0.85 (collection efficiency). 5) Result: annual collectable rainfall in gallons. 6) Example: 1,000 sq ft roof x 40 inches rain x 0.623 x 0.85 = 21,182 gallons per year.
Chapter 4: Underground Cistern
Advantage
Disadvantage
Mitigation
Temperature stable (cool in summer)
Excavation required
Use backhoe or hand labor
Protected from freezing
Difficult to inspect
Install access hatch
No space above ground
Pumping required
Hand pump or gravity feed from hillside
Protected from sunlight (no algae)
Waterproofing critical
Cement plaster interior
Hidden from view
Structural load from soil
Arched roof or reinforced concrete
Underground cistern construction: 1) Excavate hole (larger than cistern by 2 feet on all sides). 2) Lay gravel base (4 inches, compacted). 3) Build cistern walls (brick, stone, or ferrocement). 4) Build arched or reinforced roof. 5) Plaster interior with cement (waterproof). 6) Install inlet pipe (from roof collection). 7) Install outlet pipe (to hand pump or gravity feed). 8) Install overflow pipe. 9) Install access hatch (for cleaning). 10) Backfill around cistern. 11) Grade surface to direct runoff away.
Chapter 5: Water Treatment
Method
Removes
Effectiveness
Difficulty
Cost
Settling (24 hours)
Sediment, some bacteria
Moderate
None
Free
Sand filter (slow)
Bacteria, sediment, some chemicals
Very high
Moderate to build
Low
Boiling (1 minute rolling boil)
All pathogens
Very high
Low
Fuel cost
Solar disinfection (SODIS)
Most pathogens
High
Very low
Free
Chlorination (bleach)
All pathogens
Very high
Very low
Very low
Ceramic filter
Bacteria, sediment
High
Low
Low
Reference Card
One inch of rain on 1,000 square feet yields 623 gallons (this is the fundamental calculation for rainwater harvesting; know your roof area and local rainfall to size your cistern). 2. First flush is dirty (the first rain washes dust, bird droppings, and debris from the roof; a first flush diverter discards this dirty water before it enters the cistern). 3. Ferrocement is the best DIY cistern material (wire mesh plastered with cement mortar creates a strong, waterproof, and long-lasting tank that anyone can build with basic skills). 4. Keep cisterns dark (sunlight promotes algae growth in stored water; underground cisterns or opaque above-ground tanks prevent algae). 5. Always treat stored rainwater before drinking (rainwater is not sterile; boiling, filtering, or chlorinating removes pathogens and makes water safe). 6. Overflow prevents damage (a cistern without an overflow pipe will flood the surrounding area when full; always install an overflow that directs excess water away from buildings). 7. Screen all inlets (a 1/4 inch mesh screen at every inlet prevents leaves, insects, and debris from entering the cistern; this is the simplest and most important maintenance step). 8. Water storage is the foundation of settlement (without reliable water storage, a community cannot survive drought; a cistern sized for the dry season is the most important infrastructure investment).
