Water Cathment
A water catchment system consists of a collection area or roof, gutter and piping, a storage tank, and a delivery system.  The main component is the roof, without that, you can’t collect much water.  So, how much water can you collect?  On average, you can collect about ¾ of a gallon for every square foot of collection area.  The roof should slope sufficiently to deliver the water.

At the end of the roof are the gutters.  The gutters are designed to collect the water from the roof and deliver it to the pipes, and then into the storage tank.  Your gutter should be cleaned often, and in areas with lost of trees, some sort of leaf protection should be researched.  The less trash that gets into the gutters, the less trash there is in the pipes and tank later on.

The delivery pipes should be at least 4 inches in diameter to properly deliver the water to the tank.  Smaller sizes can cause backups in heavy rains, creating overflow in the gutter and possible damage to your system, not to mention wasting water that you could be collecting.

A screen filter in the delivery system before the tank is a good idea.  Just in case some dirt or leaves gets down the pipe, you want to kept that sort of trash from getting into the tank.  Be careful, however, and clean these filters regularly, as any type of blockage will create a problem.

Water catchment can provide for a home, even in the desert.  Coupled with conservative usage and proper storage, a rainwater system is one of the best water systems available.

Our first rainwater catchment was kind of an accident. When we first moved out here, before we had built anything, we lived in a bus. It was the perfect little starter home, until month number two when a hailstorm hit us. Hail stones the size of golf balls shattered all the windows and even put holes through the sheet metal roof. After that, every time it rained, it rained inside. We knew where the holes were and had buckets at the ready. When the buckets filled up, we’d pour them into larger containers. It was awesome. Free water without having to haul… we were hooked.

Additional Resources:

• General System Overview - a good explanation of a cathment system
• Rainwater Barrels and Supplies - decent products and good prices
• Rain Barrel Kits - mostly small irrigation types