David Mullen, a public health sanitarian with the Suffolk County...

David Mullen, a public health sanitarian with the Suffolk County Dept of Health Services, Division of Environmental Quality, tests water at a pumping station in Greenlawn on July 1, 2014. Credit: Ed Betz

When testing water, trends are critical. They reveal increasing contamination and help pinpoint sources of pollution that must be cleaned up. Trends are critical for testers, too. And in the case of the Suffolk County Department of Health, the trend lines are not good.

A steady decline in resources and personnel has impaired the department's ability to fulfill its mission. It takes and tests fewer water samples than in the past -- and only a fraction of the samples from industrial sites. It also is not well-positioned to detect new contaminants that inevitably emerge to threaten our water supply. The county recently replaced a few of the 30 workers cut over the last four years from the Division of Environmental Quality, the branch responsible for water testing, but more staffing is needed. The department is at a crossroads and must be supported properly.

While New York City worries about its reservoirs, Long Island's water concerns are focused on the fact that we sit on top of a particularly vulnerable sole-source aquifer. In Nassau, dozens of public providers and one private company test and supply drinking water to residents.

In Suffolk, the health department is one of two agencies responsible for safeguarding most drinking water. It analyzes groundwater before it reaches the aquifer and becomes drinking water.

The Suffolk County Water Authority -- which covers 85 percent of Suffolk residents; the rest are served by smaller suppliers or private wells -- tests municipal wells and filters the water. And, to be sure, the county's water supply is safe.

But the trends are troubling. Volatile organic compounds -- toxic substances in such products as paint strippers, cleaning products and automotive fluids -- are in more wells and at higher concentrations than 20 years ago. So are pesticides. As for emerging contaminants, the carcinogen dioxane -- which comes from detergents, cosmetics and a now-banned industrial solvent -- was recently detected in nearly 50 percent of tested wells. Pharmaceuticals and chemicals from personal care products also are seeping into wells.

With water sampling down by 15 percent overall, the department risks having insufficient information to properly chart and respond to these threats. It lacks personnel to sample, test and analyze the new pollutants -- and to monitor Suffolk's 40,000-plus private wells. And cutbacks to the state Department of Environmental Conservation have added to the county's workload. The staffing shortages must be addressed. The water authority, which also has a state-of-the-art lab and has increased funding for its testing program 16 percent in the last three years, might be able to help.

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On the plus side, the health department recently addressed a dramatic drop-off in industrial site testing by hiring five new workers. Dry cleaners, a major source of Superfund sites, have not been tested since 2010; now all will be tested in the next year, with staffers returning annually to check on suspect sites. And the unit will test as many other high- and medium-risk facilities as possible.

The department's testing decline has occurred as development has exploded in Suffolk. That's troubling. When more vigilance was required, less was done.

The county says its testing exceeds state standards, as it should -- unlike the rest of the state, our drinking water is beneath our feet. Critics say the department does less than it once did. Both statements are true. So, what is enough? Where is the sweet spot of testing?

The health department is working on a much-needed comprehensive water resources management plan that will help solve that riddle as it seeks ways to protect our groundwater and drinking water for decades to come. But the basic answer is simple: Testing is appropriate when it identifies problems.

Suffolk faces many threats to its water -- including nitrogen, pesticides and hazardous material spills. Testing supplies data, data help set priorities, and having priorities leads to informed decisions.

The more you do, the more you know, the easier it is to identify contamination and respond to it -- before it shows up in the water.

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