i have a ten micron water separator filling into a 2 micron set up, works ok for me so far... and a 2 micron under the hood.. I just add plenty of stanadyne and so far so good.. knock on wood..

 

Unfortunately you will NEVER get them to admit it, but you might be able to get them to help you with it. My neighbor had the same issue and we used the 5 gallon bucket method. A while later, I was talking with the guys at the co-op and they told me if I was getting a fuel delivery, they would circulate mine through a separator for me at no charge. If they came out just for that they wanted a 10 dollar trip charge or something like that. Honestly though, there should be a separator on the tank, I have one on both of mine now.

Might just be easier to bite the bullet and go that route so you never have an issue (or at least less of a hassle) in the future...

 

First, let me say that I have for a long time had one of those biggest size MR FUNNEL water-separating filtering funnels and THEY DO WORK AS ADVERTISED.

I have tested it's water-separating ability every so often by purposefully pouring a measured amount of water in with the fuel and it always catches the water.

I highly recommend anyone that has access to questionable fuel to get one; being able to safely use fuel that otherwise would be used to burn brush-piles will pay for it in the first use.



Now, as for the water in the big tank situation.

Many have already suggested a low point water trap/drain.

I retrofitted the big farm tanks at a farm where I was general manager some years ago.

Before I came along, the tanks had one more block under the forward legs, making the rear lower portion the sediment trap.

That worked fine until there became more sediment and water than the low end would hold, plus there was no means of draining it off.


I removed those extra blocks and replaced them with pieces of treated 2x8, giving the rear of the tanks just a slight bit of drop.

At the bottom-rear, I installed a downward pointing 18" length of 1-1/2" pipe.

At the bottom end of this pipe I added a TEE such that the long leg of the TEE was in line with the pipe.

I installed a plug coated with anti-sieze in the bottom of the TEE.

This plug was to be removed when a serious flushing was called for.

In the 90* facing leg of the TEE I installed a simple spigot for draining off any accumulated water.

It was easy to open this spigot into a clear plastic jug and see when water quit coming out and fuel took it's place.


On the hose end of the tanks, I installed first a cut-off, then an upward-facing TEE with a clear hose that showed the fuel-level, then a water-separating GoldenRod sediment-bowl/filter.


This system ended all of the fuel troubles that they had previously been having.

 

I am not saying that it is impossible, but it is highly unlikely that watered fuel came in the delivery truck.

These guys bread and butter is all about fuel; and, a rumor about someone getting water will spread like wildfire and ruin their business, so they are very particular about such issues.

Storage tanks are notorious for accumulating water and even growing thriving "algae" communities within their dark confines.

The steel not submerged in fuel sweats EVERY NIGHT, this sweating is compounded by the presence of cold fuel.

The more exposed metal, as in the lower the fuel level, the more square inches that get covered in condensation/sweat.

When daylight comes and the tank warms, all this water from condensation falls into the fuel.

It is like a 1/4" rainfall inside the tank every day.

The same happens in the tanks on vehicles; it just gets stirred up and mostly burned off.

 

I put an 18 gpm pump from Northern Hydraulics on my heating oil tank and run it through one of those earth filters about an hour or so a week in the heating season and several times through the summer. I went through three furnace nozzles in one month a few years ago before I did that. Installed the recirc and filter and have not replaced a nozzle in over five years due to water issues. The pump takes a suction right where the oil goes out of the tank into the normal furnace strainer / filter (low end of tank) and discharges against the far wall of the tank so it slides down the tank wall and creates circulation and doesn't foam up the whole tank. Cost about $300 or so but was well worth it to me to eliminate the moisture issues. I also try not to let the tank get below half empty (or full as it were).

 

Exactly what he said. We have some 100k emergency diesel fuel tanks where the fuel had turned to nearly sludge causing the EDG's to run really bad (the EDG at a nuke station is something you do not want to run really bad / think Fukushima for a reality check). We had to pay hundreds of thousands of dollars to an outside vendor to have the fuel recirced and filtered and cleaned up and diluted with new and on and on. Diesel fuel will grow some nasty critters under the right situations and conditions.