PORTLAND – More than 10,000 years ago, retreating glaciers left deposits of sand and gravel across the landscape of what would become Maine.

Those deposits filter Maine’s abundant snowmelt and rain before it collects in underground pools. Many people like the taste and clarity of water drawn from those aquifers.

Although geologists know where many of the aquifers are located, exploration and investment by Poland Spring suggest that Maine has barely begun to develop its spring water deposits.

While 159-year-old Poland Spring is familiar to Mainers as the name of the town and water source near Auburn that bears its name, less is known how much its parent company, Nestle Waters North America, is investing in the state.

At the same time, state government has done almost nothing to promote its groundwater resources or encourage the bottled water industry, according to Jack Cashman, Maine’s economic and community development commissioner.

“It’s an industry that has grown on its own,” said Cashman, who met with Nestle Waters executives earlier this month to hear about the company’s expansion in western Maine.

Poland Spring poured $250 million into Maine operations between 1998 and 2003, and it now has 521 employees and an annual payroll of more than $26 million.

It has springs and bottling operations in Poland Spring and Hollis, and also draws water from a spring in Fryeburg. Together, they supply Poland Spring with roughly 1 million gallons of spring water a day.

The company is now developing a new spring source in Pierce Pond Township, 100 miles north of the bottling plant in Poland Spring. That could help support another multimillion-dollar bottling plant in a few years, probably in the Madison-Skowhegan area.

The idea of drawing Poland Spring water in Somerset County and trucking it to Boston and New York markets may have seemed unrealistic a decade ago, but since 1993, Americans have doubled their consumption of bottled water.

The Beverage Marketing Corp. says bottled water became the No. 2 drink in the country last year, behind soft drinks.