Rain-water Harvesting – 6 of the best systems for your home

Very few people in the UK would consider safe, clean drinking water to be a luxury item. But as the world population increases, and as the effects of global warming take hold, the abundance of this necessity is slowly coming under threat.

Conserving water in the home can go a long way to combating this threat. By using rainwater to do the laundry, flush the toilet and water the garden, the average household can cut its water consumption by 50%, with clean water reserved for drinking and bathing. a Rain-water harvesting system will therefore save you money as well as help the environment.

The general concept behind domestic rain-water harvesting systems is fairly simple. Downpipes collect rainwater from the roof and filter it into a storage tank, removing leaves and other debris. A calmed inlet allows the water to enter the tank with minimal disturbance. The water can then be pumped, on demand, from the tank to toilet cisterns, washing machines and so on when needed. Most systems have safeguards in place, both for when rainwater is heavy and when it is scarce.

Rain Harvester Ltd - Rain-water harvesting system

Below is a round-up of six of the best domestic rain-water harvesting systems available on the market, ranging from the simplest to more complex systems.

1) Freewater UK – RainmanTMStandard T
http://www.freewateruk.co.uk/rainwater-recycling-rainman-std.htm

Freewater UK is a company based in Lincoln which prides itself on developing systems which are easy to understand, install and maintain.

The RainmanTM Standard T is the simpler of their two domestic systems. The underground tank is made of polyethylene and is heavily ribbed to ensure robustness. Unlike some other tanks on the market, Freewater UK’s is manufactured in one piece, making it completely water-tight. Three capacities are available: 3,300 litres, 4,700 litres and 6,500 litres.

Within the tank is a two-step, cross-flow, self-cleaning filter which captures almost 100% of the rainwater while leading any other materials, both large and fine, to the sewer. Its neat placement within the tank means that maintenance access will not be obstructed.

At the bottom of the tank is a submersible, low-noise, Vertical Multistage Pump which is operated via a pump control located in the home.

Where there is heavy rainfall, an overflow siphon with rodent barrier ensures excess water is moved to a soakaway / storm drain. Where there is little rainwater, and a minimum water level in the tank is reached, a float switch in the tank activates a solenoid valve beside the pump control which ensures automatic mains water supply to the tank.

2) Ecozi – Residential Package
http://www.harvestingrainwater.co.uk/rainwaterharvesting/completepackages.html

Ecozi’s rain-water harvesting systems come pre-assembled and can be easily installed either by self builders or contractors. They are also easy to maintain: the polyethylene and polypropylene tanks have smooth internal surfaces that are easy to clean and the pump is located in-house so there is no need to enter the tank for pump maintenance. They hold 3,500, 5,000 or 6,000 litres and come with either an internal or external filter.

Ecozi utilise a Matrix rainwater management system which provides automatic mains water backup and a maximum pumping capacity of 60 litres per minute.

3) WPL Ltd - Rain Retain
http://www.wpl.co.uk/rh_homeandgarden.php

WPL’s Rain Retain system utilises an Optimax-Pro self-cleaning filter which captures up to 95% of incoming water. It also incorporates an in-house pump system, which allows for easier maintenance compared to in-tank pumps.

WPL offers a range of tanks with its system. Carat tanks are the norm, which are available in 3,750 litre, 4,800 litre and 6,500 litre capacities. Each has a fully rotatable tank head. This allows you to install the tank at any angle to the house and the head can be aligned to the piping.

Rondus tanks are ring-shaped which provides more stability. This is particularly useful for installation in groundwater and cohesive soil. It is available in 2,000 and 3,000 litre capacities.

WPL also offers tanks which can be kept above ground. The Herkules is the strongest of these, constructed of reinforced polypropylene and able to hold 1,600 litres. They are space-consuming, however, and WPL’s Column tanks may be better alternatives, as their height means the tanks take up less ground space. Column tanks are available in various capacities ranging from 330 to 1,000 litres.

Regardless of which tank you choose, the system will include an overflow siphon with a rodent barrier and a float switch which activates the mains water supply when the water level drops.

4) Rainharvesting Systems Ltd – Domestic System
http://www.rainharvesting.co.uk/pages/systems/domestic.html

The domestic system from Rainharvesting Systems Ltd employs a self-cleaning WISY WFF vortex filter which captures around 90% of incoming rainwater. Tanks are available in glass-reinforced plastic, concrete and polyethylene and come in underground and overground versions. Capacities range from 1,500 to 7,500 litres.

The stainless steel, submersible pump produces little noise and has a maximum pumping capacity of 80 litres per minute. A ‘Controlmatic’ flow controller automatically controls the pump when required and can automatically switch to mains water when the tank starts to run dry.

A wall-mounted tank gauge can be fitted as an optional extra. It displays the water level by measuring the hydrostatic liquid pressure at the bottom of the tank, and can also display the temperature.

5) Freewater UK – RainmanTM Elite
http://www.freewateruk.co.uk/rainwater-recycling-rainman-std.htm

The RainmanTM Elite is the more sophisticated system produced by Freewater UK. The main improvements over the Standard T are a ‘MicroRain’ microprocessor and a patented Remote Integrated Measurement (RIM).

The MicroRain microprocessor replaces the pump control in the Standard T system and uses a 32 character LED display to provide the tank level percentage, system pressure and alert you of any leaks or pipe breakages. MicroRain can also used to manually test each component in the system as well run an auto test on a 30 day cycle and a timed automated filter wash on a 14 day cycle.

MicroRain utilises pressure / flow sensors to operate the pump, rather than relying on moving parts, making the Elite more efficient than the Standard T.

The RIM system monitors rainwater level in the tank and automatically maintains a minimum level from the mains water supply.

6) British Eco.com - Professional
http://www.britisheco.com/category.aspx?categoryid=195

British Eco.com provide a 15 year warranty on their tanks which, as with those from Freewater UK, are manufactured in one piece to ensure they are watertight. The 1,300 litre tank is suitable for underground and overground use, while the 3,500 litre and 5,000 litre tanks are developed for underground use only.

Rain Harvester Ltd - Rain-water harvesting system

A T50 Downpipe Filter and a CS1 Multistage Filter work together to ensure the water entering the tank is 95% pure, which is sufficient for normal rainwater use.

This professional system includes a ‘Super Rain’ rain management which, like most, provides automatic mains water back up if the tank runs low on water. Unlike most, however, Super Rain does not use the mains water to fill up the tank. Instead, it directs it straight to the appliance. This means that only enough mains water is drawn upon when needed, thus saving water which would otherwise be spent topping up the tank.