Water Sense – Water Saving Technologies for Buildings

By Mona Ip 12 January, 2012

GreenLink Global’s Mona Ip lists out ways of saving water in buildings to save costs and protect asset values.

There’s been a lot of buzz about green buildings in recent years.  But in the pitch for green buildings, “cost savings” are critical – invest in energy efficiency and you will save money over the medium- and long-term AND reduce your carbon footprint.

But wait – water scarcity is amongst the top environmental concern in the world, so why does energy efficiency receive the whale’s share of attention in green building discussions? Problem is, water is cheap and so paybacks don’t look as attractive, especially as we obsess about rising energy costs and saving money.

Contrary to popular belief, building owners are more concerned with asset values than operating costs, even though they understand green measures can lead to significant savings¹.  And although it is often overlooked compared to “cost saving” energy efficiency measures, optimizing water efficiency is critical to protect asset values and mitigate risk.  In other words, ignoring water saving technologies because of a short-term focus on dollars and cents is simply poor risk AND asset management in today’s water-constrained world.  Particularly when it is anticipated that increasing competition and acute shortages of freshwater will lead to sweeping systemic transformation for virtually every industry worldwide over the next decade².

Even better, water saving technologies are often cost-neutral or relatively inexpensive, readily available and easy to implement in commercial, residential and industrial contexts. There are certainly ample opportunities to adopt water saving initiatives in Hong Kong.  Sure, we are the number one city using seawater for flushing (80% of households use seawater for flushing toilets).  However, we should be less proud that Hong Kong’s household consumption level is higher than many major cities – our domestic water (fresh and sea-water) use of about 220 litres per capita per day is substantially higher than the global average of only 170 litres³. (For more information, please see 8 Things You Should Know about Hong Kong Water.)

To show how this all makes “water sense⁴”, here’s a list of some proven and practical water-efficient technologies for commercial and residential buildings in Hong Kong that can help us to save more than just money:

Water harvesting

The collection and reuse of either rainwater or grey water to replace or reduce consumption of potable water is not a new concept – in fact, there’s archaeological evidence that rainwater harvesting dates as far back as 6,000 years ago in China⁵.

Today “multi-source, multi-use” strategies and improved technologies to capture, clean, store and reuse water allows replacement of 90% of water in commercial buildings with harvested, on-site resources⁶. Imagine the possibilities for shopping centres, schools, hospitals and office buildings and more – that is a lot of water savings!

Water meters

To improve water efficiency, you should begin by monitoring and understanding your building’s water demand and consumption patterns.  From there, you can select the best conservation initiatives to maximize water savings (and get the most bang for your buck).  Water metering is also a critical part of “Smart Buildings” – this includes using sensors and controls that can help with leakage detection. Some estimates show that an average of 15% of domestic water usage is due to leaks⁷!

Low flow, dual-flush toilets

In a domestic setting, toilets alone account for 40% of water usage.  Switching from a typical 3.5 gallons per flush toilet to the low-flow dual-flush variety that uses as little 0.8 gallons a flush for liquids and 1.6 for solids will reduce water usage by up to 67 percent⁸. Today, there are many options for competitively priced low flow and dual-flush toilets with excellent performance.

Water saving fixtures and appliances

Studies show that domestic indoor water demand can be reduced by a whopping 25-37% with the use of water saving devices⁹. Water-efficient plumbing fixtures can include low-flow shower heads and faucets as well as aerators, which change the composition of the flow to include more air, which means water pressure remains consistent (and can thereby reduce water flow by 50%!)

Retrofitting with plumbing fixtures designed to save water can save a household over 11,000 gallons of water annually¹⁰. Using appropriate water saving fixtures and appliances means that the energy required to heat water is also reduced – so retrofits can easily translate to both water and energy cost savings, as many water saving fixtures are cost neutral.

Building-wide water filtration

There are a number of benefits of building water filtration, not the least of which is ensuring safe and healthy water to all occupants.  Although Hong Kong water is of relatively good quality, it still contains varying degrees of impurities and “hardness” which leads to build up of scale and ultimately can clog pipes, lead to breakdowns or leakages…

Another benefit would be to reduce reliance on bottled water – rather disturbingly, the annual volume of bottled water sold in Hong Kong is roughly equal to the volume of Two International Finance Centre. ¹¹

If you would like to find out more about what’s really inside your bottled water, read China Water Risk’s article on “Just What is Bottled Water“.

Green roofs

Not only do green roofs provide thermal insulation to reduce heat gain as well as heat loss, they are also help to reduce storm water runoff and the burden on municipal wastewater drainage systems. Choosing the right green roof system also allows for excellent water retention – there are examples of green roofs in Japan that have not required watering for more than three years and the same technologies could easily be replicated in Hong Kong.

Remember that water efficiency and conservation is also a prerequisite for Hong Kong BEAM and LEED¹².  But regardless of whether green building certification is your goal, building owners and managers in Hong Kong should adopt water conservation measures to sustain, protect and potentially improve building asset values. Adopting water saving technologies simply makes a lot of sense, failing which you could find much more than water going down the drain!