How often do, ,you water tomatoes

Are they planted in pots or in the ground?

it all depends if you have them in the ground or in pots , if they are in pots the bigger the plant the more water they need and on really hot days i would water them 2-3 a day . tomato plants tend to need a lot of water. but of course you always need to be careful to not over water them. Good luck !!

Once a week

If you can find one, there are meters that you can stick in the soil and it will tell you if you need to water. If it has been rainy, much less often even in pots. I some times even water them daily. Everything depends on how much rain you get. Sometimes it rains, but not near enough to get well down in the roots. We have an eastern facing window in one bedroom that is perfect to hang indirect light plants and we use the meter to check them because we can't see the soil and sticking a finger in the soil doesn't tell you how far down the soil it is dry. After a while a person gets to where you can judge by looking at your vegetable plants and the soil and you can tell if they need water.

Check your plants daily...look for insect activity, signs of disease, and need of water. Measure your index finger....my finger tip is about 2inches from my 2nd knuckle. When I stick my index finger into the dirt and it's just barely damp when the second knuckle hits the top of the dirt....I water. if the plants look wilted....check moisture level b4 watering. It could be to much water....or not enough.

I water mine every few days.. If it's a very hot summer and dry then I water every day. I found that vegetables do better when watered in the morning. This way the leaves dry thru the day. At night everything stays wet and damp all night which isn't good. Causes that gray powdery/mildew which wrecks your plants.