Category Guides & Reference

Estimate the gallons available from a 532-square-foot roof for any rainfall depth, then adjust for roofing, first flush, gutter losses, and tank overflow.

Calculate how many gallons a roof can collect from its catchment area and rainfall, with an efficiency adjustment for splash, diversion, and overflow losses.

Estimate collectible rainwater in gallons using roof area and rainfall depth, then subtract realistic losses from runoff, first flush, leaks, and overflow.

Set pressure-tank air precharge from the pump's cut-in pressure and tank design, using the correct drained-water procedure for an accurate reading.

Micron rating alone cannot make drinking water safe; understand what particle size a filter removes and which contaminants need other treatment or testing.

Residential water flow varies with fixtures, supply, pressure, and simultaneous use; learn how to measure GPM and judge whether it meets household demand.

Size household flow for a four-bedroom home by counting fixtures and likely simultaneous demand instead of relying on bedroom count as a fixed GPM rule.

Compare water-testing costs by deciding which contaminants matter and whether strips, a handheld meter, a home kit, or laboratory analysis fits the task.

Budget for a 500-gallon water tank by comparing material, shape, delivery, foundation, fittings, installation, and any pump or treatment equipment required.

Plan a UV water-treatment budget around unit capacity, prefiltration, plumbing changes, electrical work, installation labor, and ongoing lamp service.