Why is your sewer bill more than your water bill?

In a way, water and sewer is a lot like a two-way toll bridge… it costs us coming and going. Turning lake, river, or ground water into safe drinking water has a cost. Cleansing the resulting waste water for its return to the environment has another cost. 

Whatever the costs, customers are sometimes surprised to find their sewer bill to be as much as, or even more than their water bill. How can this be? After all, drinking water is clean, pure and healthy. Waste water is, well…sewage.

Actually, it is not unusual across the country for a sewer bill to be higher than the corresponding water bill. As environmental regulations have become more and more stringent over the past few decades, the costs of treating waste water to required levels have risen substantially.

The relative size of a customers' water bills and sewer bills depends on how various water and waste water utilities calculate their bills. We will discuss the sewer side of billing. The Boothbay Harbor Sewer District charges quarterly for service based on the amount of drinking water metered and some customers are billed a flat quarterly unmetered rate. 

Sewer charges are higher than water costs for many reasons. The major reason lies in the differences between the systems for water distribution and waste water collection. Drinking water flows through pressurized pipelines. It can move uphill as well as downhill. This means that water pipelines do not have to be constructed at grade, can follow the terrain and are typically only 5 to 6 feet deep. Since most waste water flows by gravity - sewer lines must be built to grade with a certain slope. In rolling terrain, sewer lines must sometimes be built to cut through hills deep beneath the ground and well into hard rock. Trench excavation – especially in rock - is the largest part of the cost of building a pipeline. The deeper the pipe, the higher the cost of construction.

Another cost factor lies in where the two types of pipelines can be built. Since sewers rely on gravity to cause flow, they must be built where grade can be maintained or pump stations are required to lift the wastewater so it can flow by gravity again. The District has 19 such pump stations to keep the wastewater moving to our plant. In addition, right-of-way may be acquired and cleared for both pipelines and pump stations adding to overall costs. 

The geographical sizes of drinking water distribution and waste water collection systems also affect costs. Ordinarily, and because of fire protection requirements, a community will serve more of its citizens with public water than with sewer service. Many water customers in out-lying areas are on septic tanks instead of sewers. The water utility has a larger customer base to support its operating costs, lowering the cost to individual customers.

Also figuring into the mix are the differences in the treatment of drinking water and waste water.  We will discuss the sewer side.

The complexity of waste water treatment has increased dramatically over the years. In its earliest form at the turn of the last century, waste water treatment (if it was provided at all) consisted of screening out the really big objects, then discharging the rest to a receiving water. Fifty years later came settling tanks to remove smaller solids. However, the finished product remained terribly polluted, by today’s standards. Since 1972 and over the last couple of decades, treatment has evolved into sophisticated biological systems for removing organic materials, complicated filters, and modern disinfection methods. The water released by the treatment facility is usually cleaner than the drinking water’s receiving stream. Typically, the advanced systems are expensive to build and operate, increasing the overall cost of wastewater treatment.  So, it is logical that sewer bills are higher than water bills.

If you would be interested in taking a tour of our plant, please contact our office.