Determine your out of hours water consumption
WTR02
A key source of water waste is through pipe leakage and water using appliances 'letting by', causing water to discharge straight to the drain. This activity will allow you to understand how big the issue is in your facility and whether it warrants specific focus.
Dripping taps, WC syphons letting by and absent or ineffective urinal controls are just a few of the likely sources of water waste that occurs in your facility. Add to this list minor leaks to pipework, small enough to go unnoticed and overflowing water tanks discharging direct to drainage and you will start to realize that you may be wasting more water than you would expect. This measure allows you to quantify these potential sources of wastage and determine if this is an area that warrants specific focus.
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The objective is straight forward, at a time when you would expect little or no water to be being used measure the water usage through your existing water meters. The longer the period you measure this for the more meaningful your result will be.
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The first step is to understand what, if any, sources of water you may still expect to be using. For example, if you have over night security officers in they building they will have welfare needs which will use water. For each use case you identify you will need to determine if the water usage is a constant or an ad-hoc basis and you will want a way of quantifying the usage, either by water volume or timing, such that you can better analyze the results of this exercise. For example, you may brief the security officers/ to keep a record of the time they use the washroom or when they make drinks.
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Then through the measurement period read all available water meters, ideally every 30 minutes, but if not once per hour. These readings will allow you to calculate the volume of water used in each period. Anomalies or spikes in usage should be correlated against the usage records of known water consumption to try to identify the cause. Through this exercise you will determine the minimum volume of water you are using per hour, when there are no known unaccounted for sources of use, this is your water baseload, and is likely to be derived directly from sources of waste. In the theoretically perfect building this baseload volume would equal zero, however it is likely your baseload will be above zero, potentially significantly above, which would indicate that further investigation is warranted.
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If you are paying a resource to work overnight to complete this exercise you may find that reading the meter would not keep them sufficiently busy there are a number of further activities they can complete to add to the intelligence you gather:
1- add a small dry piece of tissue paper to the bottom of a number of urinals - if you urinal controls are effective this will remain dry through the unoccupied period.
2 - place a cup under a selection of taps to capture water that may be discharge, allowing it to be measured and quantified.
3 - visually inspect WC bowls to look for a steady trickle of water being discharged into the WC bowl.
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The above three items are all steps you would take as a follow up action to determine where your unknown water usage is occurring, however if you have a resource available to you there is no harm in conducting this concurrently with the meter reading exercise.
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These further investigation activities are detailed in a separate water conservation measure titled 'Water waste gemba walk'.