Clean Rain Kits – Rain Head & First Flush Diverter | Blue Mountain Co


Keep leaves, mosquitoes and contaminants out of your Rain Harvesting system with Clean Rain. Designed as all-in-one rain heads and first flush diverters, Clean Rains are a simple downpipe solution to better quality rainwater.

Product Families
Clean Rain Advanced
Clean Rain Advanced
Multi fit outlet
Clean Rain Ultra
Clean Rain Ultra
Multi fit cap
  • Benefits of Clean Rains
    • All-in-one rain head and first flush diverter
    • Improve stored rainwater quality
    • Remove suspended and dissolved organic and inorganic fine particles
    • Keep leaves and debris out of your pipes and tank to prevent clogging and anaerobic fermentation
    • Reduce load on post-tank pumps and protect household appliances by lowering sediments and tannins
    • Keep mosquitoes, larger insects and animals out of your rain harvesting system
    • No additional first flush diversion pipe chamber required
    • Easily installed
    • Easily fits standard garden, 22mm grey water and 38mm pool hoses, and 90mm pipe ( fits standard garden, 1″ sump and 1½” pool hoses, and 3″ pipe).
  • Clean Rain FAQs

    How does the Clean Rain Smart Sense technology work?

    Smart Sense technology utilises a series of hygroscopic washers. When exposed to water, these washers slowly expand, in turn activating the valve by pushing it upwards into the seat. Water is then diverted to the outlet.

    How much water gets diverted?

    Approximately 18-30 litres or 5-8 gallons will be diverted, depending upon a variety of factors. The main factors are flow rate and the period of time since the last downfall. However, several other factors such as rainfall intensity, ambient temperature, humidity and wind will all affect the exact diversion volume.

    Can I adjust the diversion volume?

    We do not recommend adjusting the diversion volume. The hygroscopic washers divert an appropriate volume of first flush.

    My clean rain unit seems to be taking a long time to divert water to my tank. Why is this happening?

    If the unit is new, this will most likely occur because the washers require several rainfalls to properly “bed in”. For the first few rainfalls, the washers will divert a greater volume of first flush water than normal. After several rainfall events the washers will be properly bedded and deliver consistent diversion volumes.

    How long will my clean rain unit take to reset?

    The resetting process is dependent upon a number of environmental factors. Ambient temperature, humidity, wind and location are all major factors in determining the resetting period. Under dry conditions with a moderate temperature, wind and humidity, the Clean Rain should completely reset within 24 to 72 hours.

    My clean rain unit is not diverting any water – why is this happening?

    There are a few quick steps to take to get your Clean Rain diverting again:

    1. Open up your Clean Rain
    2. Feel the hygroscopic washers to see if the they are dry
      Note: If they are not dry, they are expanded and working correctly
    3. Look around and check for standing water nearby
    4. If the washers are dry, check there is no debris which bonding the seal to the body – if it is bound together, gently pull the metal rod down to release it.
    5. If there is no debris there, and no obvious obstructions, take a photo and give us a call.


    I switched my unit off and can’t turn it back on. Why is this happening?

    If your clean rain unit has been turned off it will not be able to be turned back on again until the hygroscopic washers are dry and the system has reset. Frost, snow, mist and dew can all activate the hygroscopic washers, so a few days where none of these are present will be required before attempting to turn the unit back on. If this is not possible then removing the unit and storing it in a dry environment for 1-2 days should suffice for the unit to be switched on again. For replacement hygroscopic washers or further information please contact Blue Mountain Co ([email protected]).

    Is my clean rain unit capable of handling freezing conditions?

    Your Clean Rain has been manufactured using materials that are capable of withstanding freezing conditions. If freezing conditions are expected, we recommend turning your unit off via the switch and, if you have a Clean Rain Ultra, ensuring that the cover is in place.

    There are 100mm/4″ connections yet only a 90mm/3″ outlet. How will the system handle a full-bore 10mm/4″ incoming flow?

    The clean rain system has been optimised for 90mm/3″ pipe. Although the system will accommodate 100mm/4″ pipe it will not be able to deliver 100% diversion should a full-bore flow event happen. We are currently working on developing a system capable of handling a full-bore 100mm/4″ pipe flow.

    Can I change the resetting period?

    The easiest way to alter the resetting period is with the breather holes located in the section underneath the outlet (long horizontal indentations with small holes). To shorten the reset period, align the breather holes with any prevailing wind. To prolong the reset, simply turn the breather holes 90 degrees to the prevailing wind.
    An alternative way to shorten the reset period is to remove the foam shroud surrounding the washers. It should be noted that by removing the foam shroud the diversion volume will also be decreased.

    Not enough water is being diverted to my tank/barrel. How can I change this?

    Your clean rain unit may require a diverter/flow efficiency cap. We have found that some products in the market do not have this piece. If you’re missing a diverter/flow efficiency cap, we can send this to you and provide instructions on fitting it. Look through the top of your Clean Rain to check if this cap is present. It’s a blue, disc-shaped part.

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