Eighty seven percent of Houston's waterways fail to meet state quality standards — a problem that's only going to get more complex as the city absorbs a projected additional 3.5 million residents in the next 30 years.

These concerns and others were addressed Friday at a symposium presented by the Center for Houston's Future regarding the region's water supply, water quality and green building initiatives. With growing concern over the quality of our drinking water, we sat in on a few panel discussions at George R. Brown Convention Center to wade through the muck and see how murky the situation really is.

First, some figures: Harris County has more than 67 times the number of wastewater treatment plants than any region of comparable size or population, many of which are aging small-package plants that pose serious concerns about water contamination and management. We have a $77 million annual seafood industry and water contaminants affect fishing in 75 percent of our tidal waterways.

PCBs (polychlorinated biphenyl) continue to appear in our fish and in our wells — even though they were banned in 1979.

It's not all doom and gloom, though; some of the data that indicates degrading water quality can be attributed to better and more frequent measurements, changes in standards and new methods of assessment. Still, pathogens in our public pools and chemicals in our wells remain a problem.

So how bad is it?

Panelist Kevin Wagner, associate director at the Texas Water Resources Institute at Texas A&M, says the groundwater quality is "relatively high" and that although radionuclides and arsenic exceed standards in some wells, those are "isolated circumstances." When prompted by a fellow panelist and with a chuckle, he reminded his audience that arsenic is naturally occurring.

Dr. Jim Lester, vice president and chief operating officer of the Houston Advanced Research Center, painted a slightly different picture. He says that although there's been a significant reduction in point-source pollution — pollution from say, a broken drainage pipe — there has been an increase in urban non-point source pollution from say, "toxic chemicals from urban runoff."

"Removing pollutants from the market does not remove them from the water," Lester said, in reference to the PCBs still commonly found in fish. "Land use planning is the only real way to address non-point source pollution. You need to know where you're going to put things to keep contaminants from getting into the water system in the first place. And our organic pattern of growth indicates increased non-point source pollution."

Zoning? In Houston? Lester cites the cost of treating water from Lake Houston and predicts that treatment costs for drinking water are only going up. "I've heard people at the city complain about the cost of treating Lake Houston water, but when it comes to drinking water, you do what it takes," he says.

Lester suggests municipal requirements for storm water, correcting malfunctioning septic tanks, low-impact development and storm water detention basins as solutions.

The verdict?

It's complicated. State and federal standards still don't take into account pharmaceutical contaminants, the repercussions of which are still unknown. And regionalization of our water treatment plants, though it would make them more manageable and more reliable, would have to come through the state legislature and might kick the cost of collection back onto residents.

In short, we've got a lot to clear up.