Twenty years later, it is still one of the best deals ever consummated around here.Surrounded by bickering and teetering on conflict, three counties (Hillsborough, Pasco and Pinellas) joined three cities (New Port Richey, St. Petersburg and Tampa) to form one utility company (Tampa Bay Water) that ended hostilities when it came to the market’s water supply.The deal was efficient, dependable and peaceful.Until now, that is.Tampa has negotiated a side agreement with Tampa Bay Water that it says will benefit the entire region for decades to come, but that has St. Petersburg officials worried it might eventually tear the entire partnership apart."My fear is that we are unraveling the foundation of the (agreement) and letting Tampa essentially divorce itself from Tampa Bay Water,’’ said St. Petersburg City Council member Darden Rice, who is the city’s representative on the nine-person board of directors for Tampa Bay Water. "I’m concerned the board is not aware of the complications that … could end the era of regional cooperation.’’The deal is heading toward a showdown on Monday when Tampa Bay Water’s board will be asked to approve a memo of understanding that essentially allows Tampa to begin an ambitious program that could make reclaimed water drinkable through a purification process.Okay, yuck.But other than that, what’s the problem? Well, after 20 years of bliss, it seems we have a trust issue. Now it’s important to understand that Tampa had less reason to join Tampa Bay Water than the other governments back in 1998. While everyone else relied mostly on underground wells that they pooled together for water, Tampa had plenty of surface water from rivers and springs.So Tampa used a majority of water from its own supply and relied on the utility only as an emergency backup. In other words, folks in Pasco and Pinellas needed Tampa Bay Water. People in Tampa? Not so much.And now this new Tampa Augmentation Project theoretically means Tampa will have more water at its disposal, and even less reason to share with its longtime partners. And, right on cue for the conspiracy-minded, Tampa is talking about a new water supply deal with Polk County.Thus, the question of trust.Tampa officials say everyone will benefit because there will be more water to spread around. But the deal essentially means the rich will get richer in terms of water supply, and that makes some people nervous across the bay."If anyone is worried that we’re trying to tear Tampa Bay Water apart, the truth is anything but,’’ said Brad Baird, Tampa’s administrator of public works. "This won’t make Tampa Bay Water weaker; it makes it stronger.’’Not so long ago, Tampa tried to strong-arm the partnership on this deal and was rebuffed. Then the city tried going through the Legislature and lost that fight, too.This time, the city took a softer approach in negotiations and seems to have convinced Tampa Bay Water’s staff that the parameters of the deal are sound. Tampa has also sweetened the pot with a $7 million offer to the utility that would theoretically make up for water the city will no longer need to buy.So is it a good enough deal for Pinellas and Pasco?If the Tampa Bay Water board says no, a 20-year truce may end on Monday.