Fixing leaks and the Internet of Things

In a previous post, I wrote about when it makes sense the fix leaks (or not) depending on local conditions. Unstated but looming large in that post are some important questions (non-exhaustive list) : 

• where are the leaks?
• how big is each leak?
• what is each leaks' financial cost?
• what is each leak's environmental cost?

I'll now discuss briefly the issue of finding leaks. Traditionally, we have looked for leaks using a combination of sound, gas, and modeling methods. Today, connected objects offer new opportunities.

Sound and gas methods basically involve surveying the water network to listen for leaks or detect leaking tracer gas. Fixed or mobile listening devices can help triangulate a leaks' location, and tracer gas will leak (or not) downstream of where it has been injected - so the search can be optimized. These methods either reveal little information about the size of the leak, or are limited in physical reach. 

Hydraulic modeling makes it possible to focus the search for leaks. However, hydraulic models need field data to be reliable. Unfortunately, it is very difficult to take an instantaneous picture of a water network unless one has a significant number of sensors that are well-calibrated, functioning, and transmitting all at once. As a result, hydraulic models, while sometimes very precise, do not provide instantaneous information about the location and volume of leaks.

Enter a number of companies (i.e.: Visenti) that have combined the power of connected sensors with Big Data to monitor water networks in real-time to identify leaks and bursts as they happen. Connected water networks can update centralized control centers like SAUR's CPO to make it possible to prioritize leaks and react accordingly. We will shortly see the proliferation of connected objects along water networks, from sensors to meters to valves, in step with the capital campaigns of water utilities. 

Water network sensors must be placed at critical points in physically extensive systems (100s to 1000s of km), often in wet, buried, or even corrosive environments. Changing batteries is expensive, and power is not always available. Sensors therefore must be highly energy efficient and resilient, and their communication protocols must be able to overcome specific challenges. Because utilities are often strapped for cash, a major challenge is establishing an appropriate price point and clearly spelling out the ROI of these investments.   

That said, the Internet of Things, and in particular the Internet of Water Networks, is clearly the way of the future for leakage management - and other aspects of water management too. It will provide that elusive instantaneous picture of what is happening on the network, and allow engineers and technicians to increase their efficiency in reducing leakage rates. 

In a future post, I'll discuss why it's not enough to deploy sensors: utilities have to learn how to use them and transform themselves correspondingly. 

Should you reduce that leakage rate?

Recent articles in the French press have reported that 20% of all drinking water is lost to leakage in France. Although it hides significant local variability, this large a number warrants attention, in particular as France misguidedly set a 15% national target in  2010 (as part of Grenelle II). 

Water is the only industrial product intended for human consumption that is delivered 24/7/365 to all homes in France (and in developing countries in general). Drinking water cannot be economically shipped over large distances, and so is most often consumed close to its production site. For a given city or area, the cost of producing and delivering water depends significantly on geography and topography, and on the quality of available water sources - it is very much a local variable.  

Drinking water production and consumption represents (on average) a small percentage of the total water consumed in any given area. Most water is used for industry (including energy) and agriculture. However, this average can be different in places where there is neither industry nor agriculture, and where drinking water outtakes represent a significant proportion of water extraction from the environment. 

Repairing leaks is a significant expense for many water utilities. Finding leaks can be tricky and repairing them typically involves digging out old pipes - and usually replacing them. Instead of applying a uniform target leakage rate, it makes sense to optimize decision-making to local conditions. We see from above that there are two main 'costs' to consider: 

• The financial cost of drinking water production and delivery is lower :  
• in a densely populated region 
• in a region with nearby, plentiful, and clean water supplies
• in a region with favorable topography (water flows downhill for free !) 
• The environmental cost of drinking water production and delivery is lower: 
• in a region where it represents a small percentage of the total water extracted from the environment. (waste water effluent doesn't count because leaked water is 'clean'.)
• in a region where it requires less treatment and/or pumping (environmental impact of shipping and using chemicals and energy).

To decide whether or not to pursue an aggressive leak reduction strategy, we can use a simple heuristic:

	Low financial cost	High financial cost
Low environmental cost	Fix only biggest leaks - tolerate relatively high leakage rate	Prioritize leaks according to financial costs
High environmental cost	Prioritize leaks according to environmental costs	Aim for low leakage rate - prioritize with financial & environmental costs

This heuristic is better than the traditional approach, which is to consider the diminishing marginal value of leak reduction (the more leaks you fix, the smaller the marginal value of each fix), because it considers the value of the environmental impact of water leak as well as their financial impacts. It is up to each regulatory body and utility to decide together on the applicable thresholds between 'low' and 'high' costs. Most importantly, it should be done at the most local level possible to ensure that specific conditions can be taken into consideration in setting the most appropriate target leakage rate.

A fair price for water - a radical proposal

The problem

Water utilities around the world are struggling to make ends meet, particularly in the developing world, and as a result have trouble providing basic services to ever growing populations.

The price of water is a highly political and emotional subject and some people will argue in the same breath for free or cheap water for all on the one hand, and for environmental conservation on the other.

I intend to show that this position is both illogical and irresponsible, and to propose a solution to make water affordable to all to ensure access and expensive to all to ensure conservation.

Before going any further, it is important to point out that one rarely pays for water itself, but rather for water service. The distinction is important: you pay for the convenience of having water come to your taps (hopefully 24/7/365), not for the resource itself, which is not for sale. In some cases, the government applies a water tax or levy that is meant to compensate the state/community for the uptake of raw water - this is a good idea that promotes conservation, but it is a tax, and not a fee levied by the service provider, be they public or private.

The reasons behind the problem

In a previous post, I discussed the technical elements of a water/wastewater system. In theory, the price of water/wastewater, as paid by consumers, should reflect the expense of constructing/replacing, maintaining, and operating a water/wastewater system on a per volume basis over the long term. This is to say that each consumer should pay according to the amount of water consumed, and to the amount of pollution produced. This has the following advantages:

• transparency: it is clear what the water tariff pays for
• water service pays for water service: there are no subsidies and water/wastewater service operator is encouraged to be efficient, both technically and financially.
• polluter-pays principle: applies to wastewater and states that each should pay according to the level of damage done to the environment (a brewery does not pollute like a house)

Unfortunately, in the real world, this is not what happens.Water service regulators put customers into categories (domestic, industrial, institutional, etc...) and apply different tariffs to different categories, sometimes using one to subsidize the other for political gain. Politicians also subsidize the construction of infrastructure, or even (gasp!) the operations of utility companies so that they can keep tariffs artificially low - again for short-term political gain and at the expense of long-term management best-practices. Sometimes, they'll even take what little cash has been collected by the utility to fund other projects (nobody's ever taken a publicity photo in front a buried pipe) - particularly if the utility operates as a city department rather than as a company (public or private).

It gets worse...

With artificially low prices, consumers are encouraged to over-consume, which in turns leads to the construction of needlessly large (and expensive) new infrastructure. Starved for revenue, the utility does not have the resources to maintain its growing infrastructure, which slowly falls apart. This negative cycle is completed when service quality is reduced, leading to the impossibility of raising tariffs to right the situation. This is something that I have observed first-hand in countless places around the world.

To break this cycle, we need a solution that will:

• guarantee that the utility company has the revenue necessary to meet its technical obligations and maintain high-quality service to all
• ensure that everyone can afford to meet their basic water and sanitation needs, including (and in particular) the poorest who tend to consume the least.
• encourages conservation by all members of society, including (and especially) the richest who tend to consume the most

The issue of affordability of water/wastewater services has been extensively researched by the likes of the World Bank. The consensus is that people (and the poorest in particular) can afford to pay up to 4-5% of their income for 24/7 water/wastewater service.

To ensure that the poorest meet their needs, a variety of tools have been imagined, the most common of which are block tariffs, whereby the price of a cubic meter (or gallon) of water increases as consumption increases. In this way, those who consume more water (typically the rich) subsidize those who consumer less (typically the poor).  This is a good-but-not-perfect system that does not guarantee that the very poor will be able to afford water/wastewater or will have an incentive to conserve water.

My proposal

I propose that the tariff each household is charged for water should be on a strict volumetric basis (per cubic meter or gallon) and proportional to this household's taxable income divided by household size. 

This is, I realize, a radical proposal that is sure to anger libertarians will not want a utility having access to their revenue information. However, it is the best way to ensure that each household pays a "fair" price for water/wastewater service, according to its ability to afford it. The volumetric price would be set so that each household would pay 4-5% of their income to meet their basic needs (roughly on the order of 100-150 liters per person and per day), no matter what their income level might be. Any surplus revenue to the water utility could be used to for water conservation or resource protection projects, or paid as tax to the government - other taxes can be lowered as appropriate.

Unlike for many other goods, nothing can substitute for water, and so there is no way for the poor to consumer 'cheaper' water without risking their health. At the same time, the ability of the rich to pay for and use water for non-basic needs is an issue that concerns everyone, not just  those 'wasting water'. We all have a stake in preserving common water resources and in setting prices sufficiently high so that all have an incentive to save water.

There is no inalienable right to consume large amounts of water just because one can afford it. At the same time, it is morally and politically necessary to ensure that even the poorest can consume the water they need.

Because all societies have income disparity, the only way to meet our two objectives (affordability by all and conservation by all) is to index the price of a unit of water on income. In Finland, the penalty for traffic violations is indexed on one's income, and that is where I got this idea.

Why we pay for water.

As an engineer primarily focused on the financial aspects of water service provision, I have developed some knowledge of what it takes - technically and financially - to bring water to your tap and to take sewerage back out again. This first post will address the technical aspects.

To put it briefly, the water part of the system is composed of the following:

• an intake, where raw water is taken from the environment : wells, river or lake intakes, rainwater harvest, etc...
• a water treatment plant, which is more or less sophisticated depending on the quality of the raw water
• a distribution system, which is more or less extensive depending on the size of the city and the density of the population (sometimes 1000s of km for a single city) and almost always includes reservoirs or water towers
• pumping stations, which keep the water pipes under pressure to ensure that pollutants cannot enter the system through leaks - better to waste some water than to allow MTBE (for example) to enter through a cracked pipe - and to move water uphill when needed.
• house or building connections, where meters measure the flow of water into households.

The wastewater part of the system is the mirror image of the water system:

• house connections through which sewerage will flow into the collection network
• a collection network, preferably not under pressure to prevent the occurrence of anaerobic conditions and leaks to the environment
• pumping stations to move waste uphill, when necessary
• a wastewater treatment plant to treat the sewerage - more or less sophisticated depending on the nature of the sewerage, the sensitivity of receiving waters, and the regulatory environment
• an outflow pipe, to discharge the treated wastewater into the environment.

An artists' view of the systems can be found below (credit: Moira Wu)

Obviously, building, maintaining, and operating these infrastructures is very expensive, and they must be operational 24/7. This is both a matter of convenience and public health. In addition, empty water pipes are subject to infiltration from ground pollutants (see above), and you should never drink tap water in a city where supply is not available on a 24/7 basis. Costs are directly linked to the quality of intake water, the required capacity of infrastructure, the required quality of drinking water (up to or beyond WHO guidelines), the terrain, and the required quality of treated effluent.

In principle, the burden for recovering the cost of investment, maintenance, and operations should be born by consumers, according to how much they consume and how much they pollute (industries pollute water more than toilets, usually). In practice, costs can greatly exceed the population's ability to pay and regulations around the world vary greatly so that this rule is not always applied.

Next post: how much you should pay for water.