We pull the kitchen sink drain plug, flush the toilet, shut off the shower and figure unseen gremlins somewhere remove the soaps, food scraps, human waste and whatever else went down the drain.
The reality for towns and cities, though, is that sewers flow to the local wastewater treatment plant.
In Rochester, there's a staff of 28 skilled professionals capable of testing wastewater for such constituents as pollutants, oxygen and microorganisms.
Already, said Dave Lane, Rochester Water Reclamation Plant environmental coordinator, the plant removes 98 percent of pollutants from the sewer water it receives.
However, staff at the plant say that the general public — and large food producers — can have an impact on cost and pollutants that eventually get released into the Zumbro River.
What can you, personally, do to help keep the Zumbro River, or rivers nearest to you, clean?
Start, Lane said, by scraping your dinner dishes into the trash to avoid sending oil down the drain. Oils do not "settle" well. And that's a problem when you're trying to clarify water.
"it wasn't until about the 1500s that people started to put together some connections between waste and disease," Lane said. Water treatment evolved over the course of hundreds of years.
One of the first wastewater treatment facilities in Minnesota opened in Rochester in 1926, possibly near Silver Lake, although the specific location is uncertain.
The process of treating water has long used nature as a model.
Rivers, Lane said, have rapids to oxygenate their water. Oxygen helps microorganisms proliferate and they help break down organic material and pollutants. Rivers also have pools, where solids settle out, clarifying water even more. They also have exposure to the radiation of sunlight.
"We use the same technology that the rivers use," Lane said.
The Rochester wastewater treatment plant uses oxygen for aeration, like the rivers' rapids; settling out of solids in pools, like the pools of a river; and disinfection like the way nature uses sunlight to disinfect water.
The Plainview wastewater treatment plant uses ultraviolet light for disinfection. Rochester uses chlorine.
Not to drink
We're not talking about drinking water. Drinking water comes from deep wells stationed around Rochester that bring water up from the water table far underground.
It can take anywhere from a year to 100 years or more for water on the surface, such as effluent from the Rochester wastewater plant, to soak into the water table. By that time, it's been through the river, perhaps become rain and/or soaked through layers and layers of clarifying soil and sand.
Lane said a newspaper article describing the new wastewater plant in 1926 noted the "new plant will end complaints of farm owners" who complained of "putrid conditions" downstream from Rochester's bustling early community.
The folks downstream from any wastewater location are often the ones who spur change upstream, Lane said.
Thus, he's hoping the downstream users (in other words, the general population) will realize the importance of helping to keep rivers clean.
Lane suggests skipping exfoliant facial scrubs that have been shown to contain tiny plastic pebbles which float (meaning they don't settle out during the processing of wastewater). Instead, he said, use exfoliants with natural ingredients made from walnut shells or apricot shells. Do not flush medicines down the toilet or pour them down the drain. Instead, take them to the City/County Government Center in Rochester or to drug reclamation sites elsewhere.
Wipes to trash
Lane also says residents should toss baby wipes, counter wipes and facial wipes in the trash can, not into the toilet. They get wound around equipment, must be removed by (gloved) hands and are sent, eventually, to the incinerator in Rochester, which is where trash ends up anyway.
If residents take that step, they'll save considerable cost and time for the city, Lane said.
"It's called toilet paper for a reason," he said. "All other paper should go in the trash." Same goes for dental floss — it should go in the trash can. And skip using antibacterial soaps, which can counteract the wastewater treatment plant's need for natural bacteria that break down wastewater solids and pollutants.
Large Rochester food producers, in particular, have become helpful at alerting the wastewater treatment plant ahead of time when they have large accidental releases of a few hundred gallons of fluids, such as milk. That can overwhelm the plant's bacteria. But a quick phone call from a food producer can alert the plant to take proactive measures when a large influx of wastewater is on the way.
Lane said anyone can tour the plant, from third grade to old age (kids younger than that aren't generally tall enough to see plant operations). To arrange a Rochester Water Reclamation Plant tour, call 507-328-2650.