Dissecting ISO 37120: How sustainable is your city's water supply?

Wed, 2014-12-03 06:00 -- SCC Staff


By George Karayannis, LEED AP

We continue our series on the new ISO 37120 Smart City standard with a look at the last of 17 themes defined in the standard: water and sanitation.  As previously described, ISO 37120 includes 46 ‘Core’ (must report) and 54 ‘Supporting’ (should report) indicators.  The water and sanitation theme has four core and three supporting indicators.

Less than 1% of Earth’s water is potable -- meaning water that’s clean enough to drink. Even though clean water makes up just a tiny fraction of all the water on our planet, there should be enough of it for people to live.

But there isn’t, and it’s a critical problem. While someone could survive a month without food, without water, they could survive only a week or less.

Worldwide, some 780 million people don’t have access to clean water, and it’s almost exclusively a problem in Africa and southern Asia. That water shortage kills nearly 3.5 million people each year. The death rate among children would be similar to a jumbo jetliner crashing every four hours, according to the World Health Organization and UNICEF.

Beyond the health issues, there’s also a tremendous opportunity cost. In many African villages, women and young girls spend several hours each day fetching water from a community source. For some, that trip is as long as six hours. For girls, that is time they are not in school learning and developing skills.

With such a substantial impact on health and quality of life, the ISO 37120 water and sanitation theme is one of the larger themes, ranking in size with energy, the economy and solid waste management. Together, the theme’s core and supporting indicators measure the quality, quantity and reliability of access to clean water.

But the indicators also go beyond human health measurements since basic access to clean water simply isn’t an issue in developed countries. In fact, throughout all of the developed world -- the United States, Canada, Japan, Australia, New Zealand, Russia and all European nations -- just 10 million people don’t have enough water. That’s barely 1% of the world total.

Likely for that reason, the indicators go beyond basic access to water to also measure whether communities are supplying their residents using sanitary, sustainable sources with minimal environmental impact. To meet the overall smart city standard, cities will likely need to find ways to ensure that very little water is wasted.













Core Indicators

1.    Percentage of city population with potable water supply service

Obviously, this number should be 100%. But this indicator doesn’t just consider the source of the water, it also considers how the water gets into a home. For a home to count as having potable water service, the water must be delivered through a pipe or other high quality duct. Rubber hoses, bamboo and other connections prone to failure and contamination do not qualify.

2.    Percentage of city population with sustainable access to an improved water source

An improved water source is one that is protected from outside contamination, especially fecal contamination. In most cities for most residents, the improved water source is a connection to a public supply, but it doesn’t have to be. Public taps, protected dug wells, protected springs and even rainwater collection can count.

This number should also be 100%, and in many developed areas it already is. The World Bank tracks it on a country-by-country basis. The U.S. falls just short at 99%. Most European countries, including the United Kingdom, Germany, Spain and France are at 100%. Many African countries, and therefore many of their cities, fall well short of the goal. In the Democratic Republic of Congo, just 47% of residents have access to an improved water source. The number isn’t much higher in Ethiopia, Mozambique and Madagascar, among others.

3.    Percentage of population with access to improved sanitation

Improved sanitation goes hand in hand with clean water. If sanitation is poor, waste can contaminate the water, spreading disease. More than 1.5 million children die each year from waterborne diseases.

As with improved water sources, improved sanitation can cover quite a range. Flush toilets that empty into piped sewer systems, septic tanks and ventilated improved pit latrines count, as do composting toilets. Public and shared toilets, open pits and pit latrines that don’t have slabs are among those that do not.

In developed areas, the percentage, if not 100%, is very close to it. This is a measure, however, where other areas lag even farther behind. In the Democratic Republic of Congo, one of the areas where the ebola outbreak is the most severe, only 31% have access to improved sanitation, according to the World Bank. In countries such as Chad, Liberia, Madascar, and Ghaha, the number is in the teens. In South Sudan, the number is in the single digits.

4.    Total domestic water consumption per capita

This core indicator is measured in liters per day per person, and the amount of water a person needs to drink varies quite dramatically based on climate and health considerations. In a temperate climate, people may need only 2 to 3 liters per day. In hotter areas, the water needs can jump to 7.5 liters per day or more.

But domestic water consumption goes beyond that, accounting for all household uses of water. In fact, drinking water is typically the smallest use. A toilet typically uses triple that. Showers and washing machines can easily multiply the daily water use by 25 times or more.

Americans typically use about 500 liters of water per day. Western Europeans use about half that, and the average African uses only about a fifth of that.

The ISO standard does not prescribe an acceptable level of consumption, but rather one that’s appropriate for the community’s climate and resources. Green lawns and long showers can be acceptable if a city’s water supply is fed by frequent rain or a deep snow pack. In drought-prone areas, cities will need to use tools like smart meters and GIS to encourage conservation so that their water usage does not exceed their supply.

Supporting Indicators

1.    Total water consumption per capita

Like the core domestic water use indicator, this one is measured in liters per person per day, though it also includes all commercial and industrial water use. In many cities, this is where the really serious water consumption occurs. Total water consumption is often dramatically higher than domestic water use.

In the U.S., domestic water usage accounts for only about 13% of all the water used. In much of Western Europe, domestic usage accounts for about 25%.

Just as with the domestic water indicator, there is no specific usage figure that cities need to aim to achieve. Rather, the amount of water used needs to be appropriate to the water supply. Cities in very wet climates with high water use may achieve this indicator, while cities that have relatively low consumption but are in drought-stricken areas may not. The actual amount used isn’t as important as whether or not the water supply comfortably exceeds demand.

As with the core indicator, effective conservation programs may be necessary to meet the goal. Some communities have also generated great results by finding ways to reuse water.

2.    Average annual hours of water service interruption per household

This supporting indicator measures the reliability of a city’s water system and, obviously, the goal is to eliminate interruptions as much as possible. As far as the standard is concerned, any significant reduction in service is an interruption. A boil water advisory counts the same as a complete interruption.

Larger cities have much more pipe that they need to maintain, and therefore have many more points of failure that they should be concerned with. While the ISO standard does take the size of a city’s network into consideration, cities that are struggling with reliability issues may want to prioritize problem areas and deal with them as they are able.

San Francisco Water Power Sewer has undertaken a number of key projects over the past decade, performing seismic upgrades in some cases and working to improve general reliability in others. Other cities, including Antipolo City in the Philippines, have found success using hydraulic modeling to improve the reliability of their water systems, especially as they’re dealing with rapid population growth.

3.    Percentage of water loss

In most water systems, some amount of water simply vanishes between the distribution source and the customers’ meters. This supporting indicator measures that.

Utilities don’t want to lose any water, but it happens. And for some, it’s a very serious problem. In Eastern Europe, utilities can lose up to a third of their water due to leaking pipes and aging infrastructure. Before recent upgrades, the city of Detroit’s leaky pipes lost more than 35 billion gallons of water each year, costing the city $23 million annually.

Water isn’t just lost through old pipes. Inadequate billing systems or fraud can also cause water loss. Any water that enters the distribution system that isn’t paid for by a customer is lost water. The Kansas Water Science Center, part of the U.S. Geological Survey, performed a comprehensive analysis of water utilities in that state and found one that lost 65% of its water.

The American Water Works Association recommends that utilities work to lose no more than 10% of their water, though any lost water is lost revenue.


George Karayannis has over 25 years of emerging technology and complex solutions sales, business development and marketing experience. He is currently Director Utility Sales, Trimble Energy and has held leadership positions at Schneider Electric, Lockheed Martin Energy Solutions, AT&T and wireless sensor startups.  He has also served as a city councilman and is restoring a 100-year old opera house to LEED Gold status. @gkarayannis

Next in the series In the final installment, we will consider how the ISO 37120 smart city standards map to the Council's Smart Cities Framework.

So far in our series: