Renting and sharing
If you rent or share a house
You do not control the boiler, the breaker panel or the roof. You still control the plan.
The honest version
Your landlord has legal duties in an emergency. Knowing them is worth more than any kit.
Find the main water shutoff, the breaker panel and the gas valve
Today. Take a photo of each one so you can find it in the dark, and send it to your housemates.
Get the out of hours number in writing
Landlord, agent or housing provider. Emergency repairs have statutory timescales in the UK and across the EU, and most US states have habitability rules. Written requests are what enforce them.
Share the cupboard, not the argument
In a shared house, one agreed shelf with water, canned food and a flashlight, paid for between you, avoids the entire question of whose beans those are.
Contents insurance is the real preparedness
It is cheap, most renters do not have it, and it is what actually puts a flooded home back together.