How much does a Reverse Osmosis System affect your water bills?
How does an Reverse Osmosis (RO) Water FIlter System affect your water bill?
This can be quite easily calculated.
We measure water usage in cubic metres (one cubic metre is equal to 1,000 litres). We then multiply this by the charge per cubic metre. For Thames Water rates 2016/17, the volume charge for water is 128.37 pence per cubic metre, and for wastewater is 81.60 pence per cubic metre.
Therefore, we can calculate the cost as follows:
1) Assume that in the worst case scenario the RO system creates 10 litres of waste for every 1 litre produced (NB - this is dependent on the incoming water pressure and the level of the tank fullness)
2) Assume we use 20 litres of RO water per day and the waste level is 200 litres.
3) Cost of waste water per litre = 0.816 / 1000 = £0.000816 per litre
3) Cost of waste water per day = £0.1632p
4) Cost of RO waste per year = £59.56
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The difference between tank based RO systems and Direct Flow RO systems
Tank based systems typically use 50 GPD (Us gallons per day) and have a pressurised with a bladder. When the tank is empty the back air pressure is around 5-7 psi but when it is full the back pressure is around 40 psi. Therefore when using an RO from a position of where the tank is full or nearly full, due to the higher back pressure, the level of waste water will be higher than if the tank was empty and this ratio continues proportionately.
In contrast, Direct Flow Reverse Osmosis Systems, such as our best one the BMB Nova Pro, have large membranes (two 400 GPD membranes) which then give a decent direct flow of water 1-2 litres per minute and minimise the level of waste due to there not being an RO tank involved.
The Osmio Zero has been a revolutionary product updated in 2019 which has kettle funtionality as well as being producing and innovative way to recycle the waste to minise the rejection level to only 1 litre waste with 4 litres of pure and low TDS water. FInd out more: the best zero waste reverse osmosis system.