A diverter can be installed just before your tank or near the downspouts. As it begins to rain and water comes down from the roof and gutters it flows from pipes into the diverter. The diverter fills up with the first flush of rain from the roof. Once the diverter is full, the cleaner water flows into the tank.

What is first flush device?

A first flush diverter is a device or plumbing assembly that takes first rainwater which carries most of the dirt from your roof and diverts it from the storage tank. Generally speaking, the more water is diverted, the better the quality of the rainwater that ends up in the storage tank or recharge zone.

How long should a first flush diverter be?

Rain Harvesting First Flush Diverters are sold in kit form – just add the desired length of standard 3”, 4” or 12” PVC pipe to create the diverter chamber section.

What is the purpose of a first flush?

First flush diverters are a critical component in any Rain Harvesting system. These devices divert and capture the most contaminated, sediment-laden water that washes into your pipes from your roof during the first initial millimetres of rain.

How do downpipe diverters work?

A rainwater diverter attaches to a downpipe that runs from the roofline guttering down towards the ground, and diverts some of the rainwater into a water storage tank, instead of the water running directly down into the ground drainage system.

Rainwater Harvesting: First Flush Diverters A Waste Of Money?

32 related questions found

How do you calculate First Flush volume?

First flush calculations

Because of contamination on the roof the first volume of rain should be diverted from the storage tank. As a rule-of-thumb, contamination is halved for each mm of rainfall flushed away. Calculation: meters squared (roof area) X pollution factor= liters to be diverted.

What is a rainwater first flush?

A first flush diverter (also known as a roof washer) is a simple contraption that diverts the first flow of water away from a rainwater catchment system. The first pass of water in any storm essentially washes your roof of all the sediments that have collected since the last rain.

What is first flush stormwater?

First flush is the initial surface runoff of a rainstorm. During this phase, water pollution entering storm drains in areas with high proportions of impervious surfaces is typically more concentrated compared to the remainder of the storm.

What is first flush volume?

The first flush refers to the situation of having a very high delivery of either concentration or mass of a pollutant during the early part of the storm runoff event. The data from sixteen sites in the Auckland region and ten water quality parameters were used in the analysis.

What is first and second flush tea?

First flush is tea picked and manufactured during March-April. (So you are hearing a lot of first flush talk right now). Second flush is picked and manufactured in June-July and the autumn flush, as suggested, is tea that is picked and manufactured during October-November. Tea character by flushes.

How do I filter rainwater from my roof?

Rainwater can be filtered for drinking as long as you have a clean catchment surface and you use a proper filter. Water for the whole house can be filtered using a uv filter or quantum filtration system or you can use a gravity filter such as a Berkey Water Filter just for your drinking water.

What is the function of a first flush and filter in rainwater harvesting system?

First Flush or Rain Diverters, as the name implies, flush off the first water of a storm before it enters the storage tank. This is the water that could be the most contaminated by particulates, bird droppings, and other materials laying on the roof.

How do you flush a rainwater tank?

It's relatively simple to clean your rainwater tank, and maintain clean water throughout the year.

1. Step 1 – Wait until after summer as water will be lowest. ...
2. Step 2 – Drain your tank. ...
3. Step 3 – Remove the sludge. ...
4. Step 4 – Connect power and fill the tank again.

What is the catchment of rainwater harvesting system?

Catchments: The catchment of a water harvesting system is the surface which directly receives the rainfall and provides water to the system. It can be a paved area like a terrace or courtyard of a building, or an unpaved area like a lawn or open ground.

What is rain head?

Rain heads (also known as “Leaf Eaters”) are a head piece designed to fit at the top of vertical PVC piping. The rain head forms the screened entry point to the top of pipework that leads water into your tank. The rain head at the top of this pipework is therefore normally used below an open downpipe from your gutter.

How do you install a rainwater harvesting system?

1. Right place for water water harvester. The best place to install your rainwater harvester is next to the roof drain pipe or the down-spout. ...
2. Fixing PVC gutters. ...
3. Fix downpipes with clamps. ...
4. Installing washout pipes. ...
5. Storage tank filter. ...
6. Placing the storage tank. ...
7. Tank overflow pipe.

How is rain water calculated?

For this reason we can generally assume that only 90% of the rainwater can be collected. For calculation we take the following formula: mean annual rainfall in mm x area in m² x runoff factor = collected rainwater in litres. ... 450 x 120 x 0.9 = 48 600 litres.

What size is rainwater pipe?

Rainwater downpipes are most commonly round in section, but may be any shape. They typically have a diameter ranging from 50 - 150 mm, but any size can be used.

How many downpipes do you need for a roof?

From Figure 3.5 (A) in AS/NZS 3500.3, the maximum catchment per downpipe is 47m². To calculate the minimum number of downpipes, divide the roof catchment area by the allowable maximum catchment per downpipe. To calculate the average catchment per downpipe, divide the roof catchment area by the number of downpipes.

How do you connect two pieces of downpipe?

If you need to add an additional length of downpipe, join the two parts with a downpipe pipe socket and pipe clip. To allow for expansion, leave a 10mm gap between the end of the pipe and the bottom of the pipe socket. Then attach a pipe clip over the joint.