How Can I Tell if My Water Pump is 120V or 220V?

Replacing a submersible well pump or surface water pump always starts with two questions: what kind of voltage is the existing pump using (110V, 220V or 460V) and what HP is the existing pump. Even if the stickers on your old pump have worn off from age, and you can't quite tell what you have anymore, we're going to help you tackle the first question here! 

Check the Starter Box by the Well 

This is the obligatory first check, look for the rectangular grey box that the pump wires run to. If the sticker hasn't rubbed off, you should see the model number (which you can give a quick google search for and find the voltage answer in a manual or spec sheet) or even the voltage number itself on the cover, or sometimes, inside the cover. 

Investigating the Breaker 

Start by taking a look at your electrical breaker panel and removing the panel cover. 

Is the breaker that turns the pump off a single-pole breaker (identified as 120V) or a double-pole breaker (identified as 240V)?

Number of Wires 
Next you could check the wires either at the junction box or pump end.

If there are 3 wires that is a 120V pump.
If there are 4 wires that is a 240V pump.

Using a Voltmeter

If you are still not sure, using a voltmeter/multimeter is a great tool. (Make sure to read instructions for safe usage)

Disconnect the wires from the water pump exposing the wire end. Next set the voltage range to 120V to 240V. Then place the probes on the wire ends ensuring proper contact. Lastly turn the power on to the pump and check the readings on voltmeter/multimeter.