SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Moisture sensors are only reliable if you have them planted in all areas of your property. You might have one moisture level in a shaded area and another in a lighted area.
Unless you have a sophisticated moisture sensor system (which they do have). I dont see the point of having one unless your areas in completely consistent in soil and exposure.

As for piggy backing 2 sensors- I dont see how that will work effectively also.

Maybe someone else would answer differently

Since you want to use the soil moisture sensor in your particular situation,
I would just depend on it, since when it rains it will be activated when
the rain has provided enough moisture. You don't need the rain sensor.
Aquamatics comment also must be taken into account though, if you have
anything more than a simple zone to monitor. If you have lots of zone then
you need lots of moisture sensors and needs to be somehow tied to the
specific zone valve. A single sensor input on a multizone controller
won't cut the mustard. What we need is a multizone controller with
multizone sensors inputs or a sensor that can be tied in series to the
individual zone solenoids. Hope this helps.

I live in a 60 unit townhome HOA. We have been wasting water for years. I see the sprinklers on when its raining. What should I advise the board to look into to save water and money?

Quoted from "janie"

I live in a 60 unit townhome HOA. We have been wasting water for years. I see the sprinklers on when its raining. What should I advise the board to look into to save water and money?

It kind of depends on how the system(s) are controlled. Some complexes are watered by a single system with one central controller, and some are watered by numerous small systems, each with a separate controller.

Janie, I'm going to assume that you want something that is relatively inexpensive and will fit existing hardware.
Basically you need a rain sensor. Now, understand that a rain sensor will not turn the water off immediately when rain starts. It will stop the irrigation after a certain amount of rain has fallen. This amount is preset by the owner.
It will also not allow irrigation again until the sensor has dried out, which, in theory, is at about the same rate as your soil.
Sensors are fairly cheap and easy to install. Look HEREfor an example. If your area suffers freezing you might consider a rain/freeze sensor like THIS. All these are also available as wireless if you need that.

These will definitely help save water and money. There are more elaborate sensors out there but they get brand/model specific.

Another thing to consider down the line when your controller needs replacing is a SMART controller. These are made by all companies and will take weather reports from your area and adjust irrigation to fit. They are more expensive up front but will pay for themselves in an application like yours rather quickly. They can save you a great deal of water. This is one EXAMPLE