Many Lehigh County Authority customers began getting their water from a new source this week when water from Allentown began flowing to them, the authority announced Wednesday.

The change occurred after the authority completed the second phase of a project that connected the two water systems and allows the authority to eventually buy up to 7 million gallons of water daily from the city.

Under that agreement, the authority is paying the city $170,000 for every 1 million gallons of water it uses daily, up to $1.2 million per year.

The new water source allows Lehigh County Authority to become less reliant on its own wells, which became a controversial topic in Lower Macungie nearly four years ago when the authority received approval to expand two of its wells near the Little Lehigh Creek. Some residents and environmentalists said more well withdrawals would have an adverse effect on the Little Lehigh.

Aurel Arndt, the authority’s general manager, said in the release that some water customers will notice a major change in that their water will now contain fluoride. Allentown adds fluoride to its water, whereas the authority does not.

Most of the water being supplied by Allentown will be delivered in Lower Macungie, Salisbury and Upper Milford townships and portions of Upper Macungie Township that are south of Interstate 78 and east of Route 100. Customers in those areas will receive a water blend with a fluoride level of about 0.7 milligrams per liter of water, according to Arndt.

Customers living in Weisenberg and Lowhill townships and parts of Upper Macungie north of I-78 and east of Route 100 will not be receiving water from Allentown, meaning their water will not have fluoride.

The authority says that customers may notice changes in the taste of their water and its hardness level.

“These [changes] will not affect the safety of our drinking water,” it said in a letter to customers.

The authority says that over the next several years it will be increasing the amount of water it buys from Allentown to up to 7 million gallons per day. At that time, customers west of Route 100 will be getting fluoride in their water.

The change has been years in the making. The authority in 2008 negotiated a deal with Allentown to buy water from the city. The authority historically has relied on groundwater wells to supply its customers, while Allentown uses multiple sources, including spring water and water drawn from the Little Lehigh Creek and Lehigh River.

LCA finished the first phase of the work — a project that cost $4.4 million — in 2010, allowing the authority to receive 2 million gallons of water per day from the city’s Schantz Spring source.

The second phase, which cost $3.8 million, was finished in December.

The authority’s water customers currently use about 7 million gallons of water per day, a number that will increase with residential and commercial development.