You’ve probably heard the saying popular in home-insulation circles that the cheapest energy is the energy you don’t use. The same goes for water.

Leaky toilets and dripping faucets can waste an awful lot of water over the course of days and weeks. Concord wants people to be aware of this issue,  with their annual Royal Leak Detection contest, which can save homeowners money and reduce costs for the citywide water and wastewater treatment plants.

But this raises a question that has often bugged me: If it’s so important not to waste water – or electricity, or natural gas, or heating oil – why aren’t there better systems to alert us?

Consider water in the home. Dripping faucets are pretty easy to notice but a toilet can slowly waste water through a loose flapper valve in the tank for months before you might notice, perhaps because you wonder why it refills so often. The city offers test kits that basically consist of dye to put in the tank, but who’s going to regularly test all their toilets for leaks? 

And if a water leak occurs in a non-obvious place, like the pipe between your house and the road, there’s no notification at all until you freak out over a sky-high monthly water bill. 

It’s even worse if, like me, you are on a private well instead of city water. If there’s a leak in a toilet or an underground line the only indication I would get is a higher monthly electric bill (water pumps are energy hogs) and it would be hard to know the cause.

Another example: My house uses heating oil for its forced-air system. It is impossible for me to judge whether my oil usage is going up or down, or doing something unusual, unless I go into the basement and regularly write down tank levels and do my own comparison. Even then, the gauge on the tank isn’t precise enough to spot fluctuations that could warn me of problems. 

Compare this to the solar panels on my roof. There’s an app on my phone that tells me, minute by minute, how much power they’re producing, with historical charts and data about weather trends that can affect output. If something goes wrong, like a panel failing, I’ll notice immediately.

It would be relatively straightforward to establish a similar mobile-warning system for anything that’s metered. If there are machines keeping track of usage to charge you a fee, they can keep track of it to inform you.

For example, software on your water meter could send an alert when, say, your daily water consumption exceeds 120% of your six-month daily average. If you had just spent the weekend washing the RV you’d ignore it but otherwise you might start looking around. Better yet: tiny sensors on the input line to every toilet could alert you to individual leaks right off the bat.

I once wrote about a New Hampshire company developing an oil-tank gauge that would send out data via wi-fi, with this goal in mind, but it seems to have disappeared. (Update: A number of wi-fi gauges for oil tanks exist, readers tell me.)

I think the reason these warning systems don’t exist is partly because energy and water have always been relatively cheap, so it wasn’t worth the effort. That seems to be changing.

The other reason is technology: it didn’t used to be simple to keep an eye on this stuff, but cheap sensors, tiny computers and cellphone networks make it really easy to create warning systems. So maybe we’ll start to see them rolling out soon, so we can all take advantage of the cheapest form of everything – the everything that we don’t need to use.

If you’re a Concord resident interested in not wasting water, check the city website  at www.concordnh.gov/leaks.