Possibly, but if that's what you need to do to survive you will. Finding and maintaining access to (aka defending) a water source is one of the most challenging parts of survival. Primarily because it locks you into a location if you let it and a quality source is a huge draw for populations - obviously.

In scenarios where you're out of municipal water a few days like is happening right now in Houston (Myself and my family have been through Allison, Rita, Ike and now Harvey) then having a water cache for a week is reasonable, though really hard to do, but that's really not what we're talking about.

I've got 40 gallons of potable water in the garage that I can tap into in an emergency. In fact, most of us do...

I have an artesian well, solar, wind, and hunt/fush/grow most of my food. The neighbor has a small farm. I'm also very remotely located.

It really isn't a prepper mentality. It's just how I prefer to live. Quite a bit could happen and my life would remain fairly unchanged.

I don't have these things so much for what people picture as emergencies. I have them because they are pretty necessary to live here. We have fairly high winds and blizzards that mean mains power is not very reliable. We have ice storms that shut things down for a while.

It's a bit of work, but it is enjoyable labor.

Can you share your location +-300km ?

Outside of Rangeley, Maine. Not far from Mt. Washington, which holds the land wind speed record. I usually get about 12' (somewhere around 3.5 meters) of snow), maybe a bit more.

Are you talking about hot water heaters?

I wonder if there are more in garages or more in basements. Hmm.

Where I live, basements aren't really a thing, but I can see how it could be problematic if the water heater was in a flooded basement. I wonder if you could rig up a manual air pump to force water out of it without using the drain tap at the bottom, though.

Most worldwide don't actually. Suburban single family homes, sure. Apartments and the like, much less so. Even less so, in non-western countries with electric under sink heaters.

portable water purifiers/desalinators are pretty useful, if you have access to any sort of water

Roof-fed tanks are becoming common where I live. The water is probably safe to drink without treatment (I spent my teenage years in a rural environment with entirely roof-fed water tanks), but boiling or chlorine will ensure that.

As a child I had a dead bird come through our Saudi compound apartment's roof-fed tank system.

Definitely an outlier but I would suggest purifying all water you consumer if possible.

Urban legend has it that dead bodies have occasionally been found in rooftop water tanks in Hong Kong.

My aunt and uncle who farm here in Scotland once thought that their water tasted a bit funny so went to inspect the water tank up on the hill that supplied their water. Inside the tank they found a well decomposed sheep.

Depends on where you live. I live in the NW where it rains for 9 months of the year and the other three months there are tons of rivers and lakes. All I really need to forage for water is a bucket and a purification system.

But I feel bad for people in places like Las Vegas and much of Nevada, New Mexico, Arizona, etc. where foraging for water means death.

Why forage when you can easily store thousands of dense nonperishable calories at home? Heading out to the woods to pick a bucket of low calorie leafy greens seems like the last thing you want to be doing in a disaster.

The last thing you want to forage for in a survival scenario are greens - no competent authority would suggest that. Cattails, tubers and the like are basically worst case scenario.

Find a low elevation place and bring your shovel, water is there for the taking. While you're at it, bring your iodine tablets or water filter with you...because while water is everywhere, so is disease.