Water pouring off the terrace is the most common sign that a house runs its pump by hand. Somebody switches the motor on, gets busy, and remembers only when the neighbour shouts. It wastes water, it wastes the electricity used to pump it, and in a dry month it empties the sump faster than the corporation supply refills it.
There are three ways to stop it. They are not equal.
1. A float switch
A float switch sits in the tank and breaks the pump circuit when the float rises. It is cheap and it needs no electronics.
What goes wrong:
- The float sticks. Scale, moss and debris build up on the float or its hinge, and one day it stays down.
- The cable fails. The overhead tank is often two or three floors from the pump. A cable on a terrace spends years in sun and rain, and it is usually the cable that breaks, not the switch.
- You cannot see it. When it fails, nothing tells you until the tank overflows — or, worse, stays empty.
2. An overflow alarm
An overflow alarm beeps, or rings a buzzer inside the house, when the water reaches the top.
It tells you about the problem, but it does not solve it. Someone still has to hear it, get up and switch the pump off. At night, or with nobody home, the tank keeps overflowing.
3. An automatic water level controller
A controller measures the level continuously and switches the pump itself: on when the tank falls to the level you set, off before it reaches the overflow pipe. Nobody needs to be home.
A good controller adds two more protections:
- A run-time cut-off. If the tank never fills — a burst pipe, no supply — the motor is stopped after a maximum run time instead of running for hours. This is what protects the pump from running dry; see dry run protection for water pumps.
- Alerts on your phone, so you know the tank filled, or that the pump stopped for a reason.
Which sensor to choose
The sensor is the part that fails, so it matters more than the controller.
| Sensor | Touches water | Typical problem |
|---|---|---|
| Float switch | Yes | Sticks, cable breaks |
| Steel probes | Yes | Scale on the probes over time |
| Ultrasonic | No | Confused by condensation and foam |
| Radar | No | Costs more than a float |
We cover the trade-offs in more detail in float vs ultrasonic vs radar sensors.
Do you need a cable to the terrace?
Not any more. A wireless sensor on the tank talks to the controller next to the pump, so there is no cable down the building to fail. A solar panel can keep the sensor charged. See wired vs wireless water level controllers.
What we install
The Nexomatic water level controller comes in 26 kits from ₹5,799, with a contactless radar sensor or a float switch. The four best-known: AquaPilot Solar Pro (₹14,699) needs no wiring at the tank, AquaPilot Pro (₹11,499) runs from a socket nearby, and the View kits (from ₹7,499) show the level and alert you and can take the motor control later. Every kit has a code and a price on the kit builder. All prices include GST; installation is ₹1,500.
If your problem is overflow today, start with the overflow page, or book a site visit in Coimbatore.