A proposed $12.5 million treatment plant has raised a lot of questions for Wareham water customers. On Monday, voters will have a final say at the annual district meeting, set for 7 p.m. in the Wareham High School auditorium. For those just tuning into the issue, here’s a primer.

Why is the Water Department asking for a $12.5 million treatment plant?

Mostly to address high levels of naturally occurring iron and manganese in the aquifer, which is where the department draws your drinking water. Too much iron in the water supply causes discoloration. High levels of manganese causes health problems.

Should I be worried about iron and manganese in my water?

According to Wareham Water Department Superintendent Andrew Reid “no.” The department is treating the water now using a solution that, while effective now, isn’t viable long term. The new plant, officials say, will provide a permanent solution.

$12.5 million seems expensive. Aren’t there less costly options. Is this necessary?

After reviewing information from the district’s engineering firm Kleinfelder, it was determined that a plant costing between $9 million and $18 million was required to treat the problem. Officials said building a plant for less would not properly address the issue. As to whether or not it’s needed, Reid notes if levels aren’t lowered, the state will likely force the district to solve the problem in the future.

If I vote “yes” what happens to my bill?

It will increase. Reid says the average customer (someone who uses 53,100 gallons of water every six months) will pay an additional $72. Currently, the average bill is $300. The department sends out bills, which are usage based, twice a year

Why is the department asking for an additional $5.5 million for “treatment?”

The $5.5 million request will only be voted on if the new plant is approved. This asks voters if they want a system in the new plant that would prevent chemicals found in pesticides, fuel additives, defoliants and other compounds from entering the water supply.

Where are these chemicals coming from?

Officials said the chemicals are most likely coming from agricultural activities taking place at nearby cranberry bogs.

Should I be worried?

Officials say no. The levels found are well below state limits. That said, the department tests for the chemicals infrequently as a robust testing program would cost hundreds of thousands of dollars annually. By installing this system, a physical barrier would be in place to prevent chemicals from entering the water supply in the event of a spill. Also, while levels are low now that may change.

What happens to my bill if this is approved?

Again, it would increase. If both the treatment plant and this system are approved the average bill would increase by $108.

Shouldn’t whoever is responsible for putting those chemicals in the ground be held accountable?

The department has reached out to cranberry growers to help with the cost of the treatment plant and system. It has not yet received a response.

What if I want to find out more?

The Wareham Water District has a comprehensive document on its website (www.warehamfiredistrict.org) that answers a variety of questions regarding both projects.