Yes, but since the tanks are underground, the temp doesn’t swing that much from night ‘til day, so it’s debatable if it’s worth the effort. I have also heard that water condenses in the underground tank and being lighter than gas, rides on top. That’s okay unless you fill up during or just after the tanker truck fills up the underground tank, stirring up the mixture and sending water to the pump.
At 6 feet deep, in most locations, it doesn’t swing much in temperature from summer to winter. Day to night, not at all. That was the point.
Water is denser that gasoline and collects at the bottom. Draw-off sumps are used to pull that out from time to time. Pump fills are placed off the very bottom.
Very little air can enter the tank as gasoline has a vapor pressure higher than the ambient. Without the exchange of air, moisture via condensation really doesn’t have a pathway in.