Water savings at lavatory sinks and showers
Principle
Much of water use in tourist accommodation is due to use of lavatory sinks and showers by customers in their rooms.
To reduce water consumption it would be necessary to either curtail the time of water use by customers, an action of limited scope because it relies solely on customer awareness, without any verification of actual implementation of suggested practices, or reduce the water flow rate, i.e. the amount of water that flows during a given lapse of time. This solution is based primarily on this second option.
Water savers are small, inexpensive and very simple devices that are placed on the tap extremity; they save water by mixing air with tap water, under pressure.
Tap water generally flows at a rate of about 12 litres a minute. This flow rate can be reduced to about 6 litres/minute (variable flow rate) using a water saver, without affecting comfort or convenience, by injecting air through the flow regulator.
Explanations
Flow regulator, flow limiter, flow reducer, foamer, aerator, water saver – all these terms refer to the same type of device.
They can be fitted on all taps, and maintain water flow at a steady rate (4 to 8 litres per minute, instead of 12, for example), with water savings between 10 and 70%. Water savers are a fitting with a grill screwed onto the tip end of the tap, with the existing tip or in replacement. They limit water flow by mixing air with the water. Whether water pressure is high or low, the water stream is gentler, giving a more agreeable contact and avoiding splashing due to excessive pressure. The water that passes through the aerators feels "foamy". Tap foamers mix air and water under pressure. The water becomes more creamy.
It is hard to distinguish visually between a conventional foamer and an economical one, and even impossible for some models.
The most efficient solution is to measure water flow.
To make a simple flow meter:
- take an empty 1 litre plastic bottle
- cut off the bottom
- replace cap and turn the bottle over
- mark lines for every 0.1 litres with an indelible marker on the bottle. Use a kitchen measuring cup and add 0.1 litre of water for each calibration.
- calibrate the bottle for 1 litre
- procure a stopwatch (those in mobile phones are not practical to keep in hand when measuring).
Measure water flow with the bottle and stopwatch:
- open tap to its fullest flow
- put the open end of the water bottle under the tap for a few seconds (measured with the stopwatch).
- you cannot measure for a whole minute because the bottle is not big enough (cf. 12 litres a minute average flow rate); the idea is to fill the bottle half full in a few seconds. Be as precise as possible.
- Note the number of decilitres, and the number of seconds. For example: 0.6 L in 3.56 seconds
- Calculate flow rate as follows: =60/(number of seconds/number of L)
Example: =60/ (3.56/0.6) = 60/ 5.93 = 10.12 L / minute
In the template of proof for Criterion 11, this calculation is done automatically.
Several criteria must be taken into account when choosing a water saver:
- Taps are either "male" or "female". The choice of water saver depends on the tap:
a "female" tap has screw threads on the inside, so you will need a "male" water saver;
a "male" tap has screw threads on the outside, so you will need a "female" water saver;
- The desired water flow: 4.5 L, 5 L, 8 L, 6 L...
- Size - aerators and flow breakers (mm): 22, 24, 28
Installation depends on the type of water saver to be fitted. In general:
- unscrew the ring at the tip of the tap;
- remove scale before placing the water saver;
- screw the water saver onto the tap end as indicated in instructions;
- check that no water leaks through by opening the tap slowly.
It is recommended that you clean the water saver by soaking it in white vinegar if/when scale builds up.
Change the tap (along with water flow reducers)
Single-handle hot/cold mixing spouts are recommended for saving water, as they regulate flow and temperature at the same time the water is turned on. Unlike double-handled taps there is no need to let water run in order to obtain the desired temperature and flow rate. The tap can be opened in a single move, without changing temperature or flow rate.
Thermostatic mixing valves set the water temperature in a more precise fashion, a system that is particularly useful for showers.
There are also push-button taps, mainly on lavatories in group accommodations for example, that turn off automatically after a few seconds, to avoid that taps be forgotten and the water left running. The timer mechanism should be adjusted according to the type of use: for hand washing 10-15 seconds is enough; for showers 25-30 seconds. This type of tap can be fitted with a flow reducer. The timing mechanisms should be checked regularly.
Pressure reducers
Water pressure at the tap depends on the location in relation to the water tank or reservoir. A "comfortable" level of pressure is between 2 and 3 bars, but the level can vary between 1.5 and 6 bars. Flow reducers are designed for a water pressure level of around 3 bars. If the water pressure in your establishment is higher, flow reducers will not reduce flow as much as desired. Ex: The water pressure in your establishment is 4 bars. The average flow rate at your taps is 12 L/min. If you buy flow reducers that are rated 3 L/min (they can be purchased for a desired flow rate) the flow rate at your taps will be higher than 3 L/min, unless you also lower water pressure to 3 bars.
If the water pressure of your water supply is over 3 bars, and you do not need to maintain this level, a pressure reducer at the main water intake will effectively reduce pressure and, consequently the flow rate.
Pressure reducers economise water by regulating the flow rate. They also protect the plumbing from excess pressure, that can produce a "water hammer" effect that prematurely wears out washing machine pumps and augments the flow rate at taps. Installing a pressure reducer will prevent this.
Checking for water leaks in the establishment is a task that should not be neglected. Some tips:
- Regularly change gaskets in taps, before they wear out
- Repair leaks at fixtures (showers, taps, WC etc.) that are noticed by customers and housekeeping staff.
- Inspect all plumbing fixtures once or twice a year, or on an ongoing basis. Keep a record of inspections.
- Install water submeters and regularly record consumption data.
- Check that the meter does not run when no tap or shower is in operation (slow periods during the day, off-season when the establishment is closed).
Implementation
See the preceding heading for more details on implementation.
Flow or pressure reducer:
- List all taps and showers at the establishment (including those used by staff)
- Check the water pressure level of your water supply. Test water pressure at 3 bars, to determine whether this level is sufficient for water supply throughout the establishment.
- Contact a supplier or suppliers for costs estimates
- Install reducers on all fixtures, or only on those where the flow rate is high.
- Check flow rates again after flow rate reducers are installed.
Water leaks:
- Find the leak
- Repair the leak or contact a plumber
Costs
Pressure reducer: cost: €50 for equipment + €50 for labour
Tap water saver: €5-10. The purchase of a water saver is amortised in just a few months.
Single-handle mixing valve spout and thermostatic mixing valve: €50 -150
Benefits
- 10-70% savings in water consumption
- energy savings, because less hot water used means less water to be heated
- significant monetary savings on water and energy bills: water savers generate savings at little cost, without changing fixtures.