Water has become a major challenge for hotels, both in terms of cost and as one aspect of sustainability programs. Reducing water usage is smart from both a financial and environmental perspective. On the cost side, water accounts for about 10% of hotel utility bills. And while the cost of water varies substantially depending on location, it is increasing faster than inflation. Data on 30 U.S. cities from Circle of Blue showed about a 53% price increase from 2010 to 2019, with many drought-parched locations significantly higher.

The Green Hotels Association cites potential water savings from sustainable practices of around 50% for hotels. This can translate to 10% to 20% off a hotel’s utility bill, from the combination of reduced total water usage and the lower energy requirement for heating less hot water. Whether you are a tree-hugger or a climate-denier (or anywhere in between), this is good reason to pay attention.

And hotels have indeed been listening. Greenview’s Green Lodging Trends Report 2018 indicates that a majority of hotels have adopted water tracking, low flow toilets, and efficient faucets and showerheads. While the survey sample was likely biased toward the 4500+ conservation-minded hotels who self-reported, this still represents significant progress.

This week’s column will focus on water management technologies. While some are well established, others reflect significant recent innovation. Many are inexpensive and can be incorporated into existing hotels, and they often have paybacks as short as one to three years. Some of them extend past the traditional domain of the hotel engineer, crossing into the realm of true technology systems. IT professionals and engineering managers alike would be well served to review the latest options together to see how much their hotels might benefit from them.

This article relies heavily on published research, but also on very useful interviews with experts at the nonprofit Sustainable Hospitality Alliance, as well as at vendor companies offering specialized solutions, including Banyan Water, Ecolab, and VivoAquatics. My sincere thanks to the individuals who supported this effort.

You Can’t Save What You Can’t Measure

The experts agreed that if there is one place to start, it is measuring your water usage. Too many hotels know how much water they have used only when they receive the bill, typically weeks or even months after the fact. And in most cases, they get only a single number representing total water usage during the billing period. This gives you no useful information on how to save water: it tells you how much water you used, but not where or when you used it.

Hotels use water in HVAC systems, guest rooms, public spaces, kitchens, laundries, swimming pools, locker rooms, and for grounds irrigation; there are opportunities to waste or conserve water in every area. But every hotel is different, and to focus on practices that can help your own water bill, you need to know where and when you are using water, then address the issues that can have the biggest impact.

A good starting point for any hotel is to use the free Hotel Water Measurement Initiative tool from the nonprofit Sustainable Hospitality Alliance.  This is also the methodology used in the Cornell Hotel Sustainability Benchmarking Index, which can help hotels understand their overall water management profile vs. comparable properties. This can be very useful in assessing the overall opportunity to reduce water usage, but it does not provide much insight into specific actions that could impact it.

Smart metering is a critical technology for this. Inexpensive meters can capture water flow, temperature, chemistry, and pressure and report them wirelessly to a building management system, corporate system, or vendor-provided dashboard. In new-build hotels you can easily and cost-effectively measure water usage for each floor (or even each guest room), kitchen, laundry, public restroom, and recreational facility, as well as for cooling towers and exterior grounds. For existing hotels, installing extensive metering may be too costly, but it still makes sense to meter at some level, even if only for exterior vs. interior use. As you learn more about your water usage patterns, you can always add meters to capture specific interior uses that might need closer monitoring.

Meters should report frequently enough to enable you to pinpoint when water events occurred, and data should be retained so it can be visualized, monitored for anomalies, and generate alerts. The Green Lodging Trends Report 2018 shows that 98.1% of hotels tracked water usage regularly, but that 96.3% did so only weekly or monthly. Modern water management systems can track usage by zone and in time intervals as short as one minute, providing much greater visibility into usage patterns and potential waste. If you can see that your water usage spikes every day between 2am and 4am in the kitchen, or that there is heavy usage outdoors every Saturday afternoon, you have important clues as to where to look for potentially wasted water.

While water is water, it can pay to concentrate your reduction efforts on hot water first. According to industrial controls manufacturer Grainger, water costs about $0.002 per gallon in the U.S., but heating it cost $0.01 to $0.02 per gallon, making hot water six to ten times more expensive than cold.

Leak Detection is Key

Leaks can waste very large amounts of water, very quickly. Meters can detect many leaks, alert hotel management, and if appropriate, shut off the water until they are repaired. An in-building leak in a high-rise hotel can cause hundreds of thousands of dollars of damage in just a few minutes as it cascades downwards. Insurance companies know this and may offer significant rate reductions that can offset the cost of a metering and detection system.

Aside from damage, leaks can significantly increase water bills. A leaking toilet can waste about 200 gallons (750 liters) of water daily. Landscape irrigation systems are highly leak-prone; Banyan Water told me that hotels average about three external leak incidents per year; if not discovered, these leaks can waste tens of thousands of gallons of water per day. Systems like theirs can automatically shut off the water and alert management before much water is wasted.

Swimming pools are another common source of water loss, both through evaporation and leakage. Leakage can be detected by comparing current to normal water flow to the pool; normal patterns will have times of the day with virtually no water flow. At a minimum, pool water meters should be read once a day at the same time, but real-time metering is more effective. Evaporation can be reduced if outdoor pools can be covered when not in use.

Products to Consider

‍Many products can monitor, measure, and reduce water usage. One label to look for (although it does not apply to all product categories) is the U.S. Environmental Protection Agency’s WaterSense certification, which indicates that the product meets certain minimum requirements for reduced water consumption. Some products with this designation may be automatically eligible for financial rebates in some water districts. A call to your water provider may uncover other rebate programs as well.

Some water management products are best suited for new buildings; while they can theoretically be installed during retrofits, the costs may be significantly higher and the payback periods longer. These include capturing water from shower and sink drains and using it for landscaping (or with treatment and separate piping, it can be used for toilets). Solar and thermal water heating may be cost-effective options in some locations. Harvested rainwater can be useful for landscaping, even without treatment.

Many other products are practical in both retrofit and new-build properties, often at similar costs. Some of the most effective solutions are low-tech. Low-flow shower heads, for example, can cut guest room water use by 50%. Similarly, low-flow and dual-flush toilets use up to 84% less water per flush. Early low-flow models from the 1990s performed poorly, but today’s low-flow toilets work well. Even without replacing toilets, many hotels have reduced water usage by placing a plastic bottle or water-filled bladder into each toilet cistern to reduce its capacity. Bathroom hot water usage can also be reduced by products like Showerstream, a wall-mountable shower unit that detects water temperature, pressure, and flow, as well as shower occupancy. When the shower is turned on and comes up to temperature, it shuts off the water flow until someone steps inside; it turns it off when they step out.

For the roughly one-third of hotels that have HVAC systems with cooling towers, there are significant water saving opportunities. One expert told me that in his experience for such hotels, HVAC water savings could easily exceed those from kitchens, laundry, and pools combined (although this is a generalization that will not apply to every hotel).

At the risk of oversimplifying a complex process, these HVAC systems use water to move warm air away from guest rooms and other spaces and to the evaporative cooling tower. Water in the system is recycled, but some of it is evaporated as it passes through the cooling tower, meaning that impurities and chemicals in the remaining water concentrate over time. After a few cycles, the water must be flushed down the drain and replaced to avoid corrosion, scaling, and biofouling in various elements of the HVAC system. Smart monitoring and real-time adjustment of chemicals can help manage corrosion, pH levels, conductivity, temperature, and bio-contaminant levels. Systems such as Nalco Water’s 3D Trasar™ Technology can increase the number of reuse cycles by a factor of two or even more, reducing water usage substantially. The technology can also reduce residue buildup inside the pipe walls and machinery, which can affect cooling efficiency and the frequency of equipment maintenance; it can also help prevent introduction of biohazards such as Legionella.

Smart landscape irrigation systems can monitor soil moisture levels and weather forecasts to minimize water usage, skipping watering cycles when the soil is already wet or when rain is forecasted imminently. Banyan Water claims that its Irrigation Insight product typically reduces outdoor water consumption by 50 to 70%. At an entry cost in the range of $5,000 to $7,000 for a typical hotel with a half-acre of land requiring irrigation, and the ability to immediately shut down zones where leaks are detected, systems like this can pay back quite rapidly anywhere water cost is high.

Pool, spa and other recreational water facilities can be addressed through solutions like those offered by Vivo Aquatics, which can both detect leaks and monitor pH and chemical levels to minimize the unnecessary use of both water and chemicals, while ensuring compliance with health regulations. Pool backwash water can also be recycled for grounds irrigation.

Hotel kitchens are major water users. Warewashing in particular requires a lot of expensive hot water, but there are numerous water-efficient solutions ranging from low-flow pre-rinse spray valves to smart systems like Ecolab’s SMARTPOWER™. Among other efficiency features, it can monitor temperature and water pressure and alert the operator to issues, minimizing the need for rewashing. Efficient dishwashers can also reutilize rinse water for pre-wash phases, and conveyer units can shut off water automatically when it is not needed. A meter on the dishwasher’s hot water supply or the nearest sink should monitor temperature and raise an alert if it is not close to 140 degrees Fahrenheit (60 degrees Celsius): hotter means wasted energy for heating, while cooler means wasted water for rewashes. Kitchen water costs can also be reduced by wrapping hot water pipes with insulation and, when the kitchen is closed, by shutting off hot water recirculation pumps and dishwasher internal tank heaters, booster heaters, and exhaust hoods.

Hotels with in-house laundry operations have high-tech options for reducing water usage. Rinse water can be recycled for the first wash of the next cycle, or ozone can be injected to improve wash efficiency. Ecolab’s Aquanomic™ laundry program reduces water usage and temperature; it is used by Hilton Hotels in its Travel with Purpose 2030 sustainability program. Xeros’ Hydrofinity™ system uses high-performance, reusable spherical polymers to extract stains with as much as 80% less water and 50% less energy.

Pressure monitors at strategic locations in the hotel can also reduce excess water usage that can occur when the water pressure is too high, by alerting staff to the issue. Proper water pressure can also help reduce maintenance cost on boilers.

The Human Side

As with most technologies, water management works best when operational practices, staff training, and guest communication are aligned. Systems designed to manage water usage require competent attention; they can raise alerts that something needs to be done, but hotel engineering or other staff need to respond. When such systems are set up, be sure to carefully tune the alerts and escalations so that the staff who need to respond get, see, and act on issues in a timely manner based on the relative urgency and severity. There is a fine balance between sending so many unimportant alerts that no one pays attention to the important ones, and sending so few that they miss the critical ones. Evaluate the need for recurrent staff training as well as system training for new hires who need to be in the loop.

Beyond pure technology solutions, staff operating practices can be adjusted to reduce water usage. Kitchens can use significantly less water simply by not using it to defrost frozen food or to melt ice, both common but wasteful practices. Fruits and vegetables can be washed in the sink rather than under running a running tap. Utensils and dishes can be presoaked to reduce the need to rewash.

Housekeepers can be trained to minimize water usage when cleaning bathrooms, for example by flushing the toilet only once. Laundry water demand can be reduced if housekeepers are trained to honor guests’ preferences as to whether towels should be reused, as well as by optional or less-than-daily housekeeping. Staff and housekeeping supervisors should be trained to report running toilets or leaky faucets or showerheads immediately (some housekeeping apps support this functionality and may even gamify the reporting to raise awareness and usage).

Guests can also help save water. While many guests want to enjoy the luxury of a long shower when on vacation, a growing number are interested in sustainable practices and might use less water if they were aware of their water footprint. A handful of companies in the connected-room space have evaluated displays (on a wall panel, tablet, or mobile app) that would help guests track the environmental impact of their stay, measuring and benchmarking energy and/or water usage. It will be interesting to see how many guests will use such systems, should they come to market. One product available now, but more suitable for home use than in hotels, is the Aguardio shower monitor. It gamifies water usage in the shower by reporting usage statistics, as well as environmental measures like humidity, in a consumer-facing app.

Conclusion

Smart water management is no longer an option in many locations; building codes continue to be updated to require more and more water-saving solutions. Even where not required, the increasing cost of water together with the emergence of cost-effective solutions means that higher-tech options will make economic sense for more hotels. If you haven’t evaluated your hotel’s water profile in the past five years, it’s time to take another look!