It seems like every sprinkler system I've ever owned (inherited from a previous owner) has eventually failed on me. In some cases, the water would not shut off, wasting lots of water until the leak was finally discovered. In other cases, the water would not come on when it was supposed to, resulting in important plants or important trees unexpectedly dying during the heat of summer.
In most cases, it is practically impossible to tell when something has failed until it is too late. When a sprinkler won't go off, often the first clue is when something has been watered so long that noticeable flooding has occurred, and sometimes if it is a slow leak that doesn't even happen. When the sprinkler doesn't come on it can be difficult to tell this as well without something dying because drip heads are often hidden around the base of plants and you can't actually see water come out when they are running.
I would like to install something new to replace any existing system, without having to worry about any of the above failures ruining my garden. However, it doesn't seem like the off the shelf stuff you find at your run of the mill home improvement store has all the features I'm looking for - or maybe I'm just not looking in the right places.
I think at a minimum a reliable sprinkler system needs to have some notion of how much water it is dispensing. This means there should be some kind of flow sensor on each line (or station) and it should report how many gallons each one has taken. If water is flowing when a station isn't on, or if some threshold is exceeded in some condition (for instance, a drip leak) it should send some kind of alert, maybe over WiFi. It could also shut off an emergency master value to conserve water until the repair can be completed. Likewise, if no water is flowing when it should be, it should cause an alert as well.
Or, if there isn't something like this, maybe something else would work. One thing I was thinking was that if there were some clear sections pipes along the run it might make it clear whether water is running or not, although this would require manually checking it at various times.
Update: It appears that Rain Bird has some support for flow sensors on some of its products, but it is ridiculously expensive... starting in the range of $350 for a controller (12 station, which is 3x more than I need) and $500 for the least expensive flow sensor (compared to ~$10 for an inexpensive hall effect flow sensor). I'm looking for something for my house, not a large business complex.
Also, I'm concerned with detecting drip leaks, and it appears that even the highest sensitivity flow sensor is in the range of 0.3L/min or 114 gallons per day.