Eighty years ago, the November 1938 issue of Popular Mechanics showed this method of increasing your ground conductivity. The addition of water isn’t even mentioned in the text. But by adding the water, the ground near the rod becomes saturated, increasing the conductivity.
The actual hint being discussed is the use of a spark plug as a lightning arrestor. The lead-in is connected to one terminal of the spark plug, with the other end grounded.
Another hint shown in the same issue is shown here. Batteries are cheap enough these days that I don’t think it would be worth trying to put together this contraption, which doesn’t look very safe. But if you really want to run your small flashlight off AC power, then wiring it in series with a 25 watt light bulb, as shown, would do the trick.