Shop the auction sites. You can still find some Belgian A-5s.

I've never been too much of a fan of the old spring operated (not gas) autoloaders, such as the Browning. Point of fact, I've never been too fond of semi-auto shotguns as a whole.

For competition, I'll stick with over/unders. However, for hunting and collecting, I love my side by sides.

If you're looking for water purification, why not look into rain catchment and a cistern.

If we were younger, we could dig it out, tile/brick it, in a few days.

Now, look at it as a two hour a day, two month project.

Although, for around $1200.00 (stimulus bribery check money), you can get a plastic 3000 gallon water storage tank.

https://www.tank-depot.com/productdetails.aspx?part=N-40635&msclkid=fae8f24f5d1b158a6979ac8e729ca87a&utm_source=bing&utm_medium=cpc&utm_campaign=All%20Products%202020_04_09&utm_term=4577404347912798&utm_content=norwesco%20%26%20plastic%20vertical%20water%20tanks%20%26%203000%20gallon%20plastic%20water%20storage%20tank%20(105558)