Most people I know that have worked in water tanks don't drink municipal water. Just FFT
And the hatch provides adequate light as long as the tender isn't craning over it blocking the sun. This wouldn't be considered a cavern, because he can surface anywhere and have air. You can view in the picture the green hose that he could have climbed out with. It was tied at the hatch and down at the bottom of the tank.
And the hatch provides adequate light as long as the tender isn't craning over it blocking the sun. This wouldn't be considered a cavern, because he can surface anywhere and have air. You can view in the picture the green hose that he could have climbed out with. It was tied at the hatch and down at the bottom of the tank.