Electric Water heater spewing like a gusher water

1. Is this a rental heater - call the rental company
2. If it’s an owned unit - Home Depot or Lowe’s - by a new heater and pay for installation

I trust you've shut the water supply off to the heater? You still have cold running water in the rest of the house?

As has been said - there's no magic to this. Replace it. Call your local furnace or water heater companies and get quotes.

The cheapest up front would be to call your gas supplier and tell them you want a rental unit installed. I have one - 20 years I've been paying $17 a month and prefer that over owning. But lots of opinions on that topic.

All of this is based on the idea that your heater has somehow failed. Usually they just stop heating, not spring a massive leak. You might have a $100 problem to solve with a local plumber, not a $2000 replacement water heater issue.

Switch to gas while you're at it.

Renting is cheapest short term but most expensive long term.

Buying is expensive short term but cheapest in the long term.

So it depends on your perspective of cheap.

An electric water heater is not very expensive, I would simply replace it and avoid renting at all cost.

Your water heater is one of the most reliable electric appliances that you have. It is likely more reliable than your fridge, dish washer, washer, dryer, TV... so it doesn't make sense to me to rent it, you will simply pay way way more in the end. Even if you are not a DIY, if it breaks, you simply call a plumber to have it fixed and you will still end up with more money in your pockets than renting it.

Buy don’t rent, especially for an electric heater. They’re cheap to buy and Very easy to replace if you’re at least somewhat handy, as there is no venting or gas installation involved, and easy to service as there are just 2 electric elements.
The only connections involved are a re/re of the wiring, and cold in/hot out water lines