Cistern & Rainwater Catchment System

Rainwater catchment isn't exotic — it's gutters directing roof runoff into a storage tank instead of letting it run off into the yard, with a pump to move it back out when you need it. The whole system scales from a single rain barrel to a real household water source.

Materials

• Gutters and downspouts directing to one collection point (most houses already have this half-built)
• First-flush diverter, installed before the tank inlet
• Storage tank/cistern — aboveground poly tank or a buried tank, sized to roof catchment area and typical rainfall
• Inlet leaf/debris screen
• Pump, plus a pressure tank if the water needs to reach household fixtures under pressure
• Overflow outlet, routed away from the foundation

The Build

1. Size the tank against roof catchment area and typical local rainfall — bigger roof and wetter climate both mean more real capacity to work with.
2. Confirm gutters and downspouts actually direct to one collection point; add or reroute downspout runs if they don't.
3. Install a first-flush diverter ahead of the tank inlet — this is not optional if water quality matters at all; it diverts the dirtiest initial roof runoff (dust, bird droppings, debris) away from the tank before the cleaner water starts filling it.
4. Set (or bury) the tank, with the inlet properly screened against leaves and mosquitoes.
5. Plumb from the tank to a pump, adding a pressure tank if the water needs to reach fixtures under real household pressure rather than just gravity-feeding a hose.
6. Route the overflow outlet well away from the foundation — a full tank still needs somewhere for excess water to go without pooling against the house.

Caveats

• Untreated roof-caught rainwater is not automatically drinking water. It's genuinely fine as-is for irrigation, toilets, and laundry — but real filtration/UV treatment is a separate, necessary step before it's safe to drink, not an assumption to skip.
• Roofing material affects water quality: metal roofing is the standard recommended catchment surface for a reason — asphalt shingle runoff carries more particulates and chemical residue than metal does.
• A first-flush diverter needs periodic draining/cleaning to keep doing its job — it's a maintenance item, not a set-and-forget part.