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Rainwater from a properly designed rainwater prefiltration and storage system can be used without further treatment for landscape irrigation, garden ponds, and most exterior applications. When rainwater is used within buildings, supplemental filtration is essential and disinfection is recommended. For toilet flushing and clotheswashing, a sediment filter will remove suspended solids which can clog and damage valves, and an activated-carbon filter will remove dissolved organic matter which can cause discoloration and odors. For showering, hand washing, or drinking, use a high-intensity ultraviolet sterilizer to kill microorganisms that could cause illness. All filtration and disinfection components should be oversized in order to maximize performance and minimize maintenance.

cannister filter


PRESSURE FILTERS: We offer an exceptional quality pressure-filter housings that accept standard 4.5” x 20” sediment or activated carbon cartridges. Unlike common filter housings, the filter pot is not twisted in place but rather is clamped with a large threaded nut. This makes disassembly easy, even after long intervals between element changes. To facilitate element changing without flooding a pressure-release button and a filter pot drain plug are supplied as standard items. Either 1” or 1.5” pipe threads are available.

UV STERILIZERS: A typical UV (ultraviolet) sterilizer consists of a UV-emitting lamp mounted within a quartz sleeve (a special type of glass tube that does not block UV) which is in turn mounted within a stainless-steel tube. Water flowing between the quartz sleeve and the stainless-steel tube is exposed to UV energy which theoretically kills any microorganisms in the water. Better units also monitor the amount of UV energy that reaches the stainless-steel tube.

UV sterilizer

UV sterilizer

The design and operation of our UV sterilizer is completely different: two UV lamps and a quartz sleeve are all mounted inside a dry enclosure, one lamp on either side of the quartz sleeve. Water flows through the inside the quartz sleeve and is exposed to UV energy emitted by both lamps. A sophisticated monitoring system measures the UV output from the lamps and compares it with the amount of UV energy that passes through the water. This approach exposes microorganisms in the water to significantly more UV energy, eliminates shadowing behind larger suspended particles, and accurately determines the exact UV exposure.

The problem with using typical UV sterilizers for rainwater is that although rainwater is a relatively high-quality water source, it can have elevated levels of dissolved organics, iron compounds, and phosphates that absorb UV energy. It is not uncommon to see the percent of UV energy transmission, called the UVT, drop below 70% to 75%, the minimum UVT required for ordinary UV sterilizers. Our high-intensity sterilizer is designed to disinfect when UVT levels are as low as 50%, a level rarely seen in rainwater.

Over time, the quartz sleeves in UV sterilizers become coated with a mineral deposit that inhibits UV transmission. The simplest UV sterilizers require periodic manual disassembly and cleaning, a difficult and messy process that occasionally results in a broken sleeeve. Better UV sterilizers utilize a sleeve wiping device, but these are not completely effective and still require a regular maintenance schedule. UV sterilizers with UV monitors are also prone to problems caused by mineral deposits on the sensors which are exposed to water. Our UV sterilizer features a motor-driven internal wiper that requires no user action, and since the UV monitoring system in our sterilizer is not in contact with water it does not require cleaning.

For general rainwater disinfection, either interior or exterior, we supply a version with a 1” ports suitable for flow rates up to 15 GPM and a version with 1.5” ports suitable for flow rates up to 30 GPM. Contact us for sizing for drinking water systems. Both units include a sophisticated microprocessor-controlled monitoring system, a 24v output to operate an optional solenoid valve to stop water flow in the event of insufficient sterilization, plus an automatic bleed system to prevent overheating that can reduce UV output.

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