Many homes in Montana rely on private septic systems rather than municipal sewer service. For homeowners who have never lived with a septic system, understanding how it operates and how to maintain it is important.

A septic system treats household wastewater on the property. The typical system consists of a septic tank and a drainfield, which work together to separate solids, treat wastewater, and return treated effluent to the soil.

Proper use and routine maintenance can extend the life of the system, reduce the likelihood of expensive repairs, and help protect groundwater.

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1. Septic Systems Require Regular Maintenance

Septic systems should not be treated as maintenance-free infrastructure. Solids accumulate in the septic tank over time and must periodically be removed.

As a general guideline:

• Have the septic system professionally inspected approximately every three years.
• Have the tank pumped approximately every three to five years, depending on tank size, household size, wastewater use, and the amount of solids generated.
• Systems that incorporate pumps, floats, controls, or other mechanical components generally require more frequent inspection and maintenance, often annually.
• Consider a maintenance or service agreement for alternative or more complex systems.

Pumping frequency should ultimately be based on the actual accumulation of sludge and scum rather than the calendar alone.

Neglected systems can result in sewage backups, drainfield failure, groundwater contamination, and costly repairs or replacement. Regular maintenance is generally much less expensive than replacing a failed septic system.

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2. Avoid Sending Large Amounts of Water Through the System at Once

A septic tank needs time to separate wastewater into layers. Heavier solids settle to the bottom of the tank as sludge, while fats, oils, and other floating materials form a scum layer near the top. Wastewater between these layers flows from the tank to the drainfield for additional treatment.

Large volumes of water entering the tank over a short period can interfere with this process. Excessive hydraulic loading may carry suspended solids out of the tank and into the drainfield, where they can contribute to clogging and premature failure.

Laundry is a common source of concentrated water use. Instead of washing numerous loads consecutively on one day, spread laundry throughout the week when practical.

Other good water-management practices include:

• Run full loads in washing machines and dishwashers.
• Repair leaking plumbing fixtures promptly.
• Use water-efficient plumbing fixtures and appliances.
• Avoid unnecessarily high water use over short periods.

The goal is not to minimize normal household water use, but to avoid unnecessarily overwhelming the system.

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3. Be Careful About What Goes Down the Drain

A septic system depends partly on naturally occurring microorganisms to break down organic material. It is also designed primarily to handle wastewater, human waste, and toilet paper.

Materials that do not readily break down can accumulate in the tank, clog piping, or reach the drainfield.

Avoid putting the following into a septic system:

• Cooking grease, fats, and oils
• Coffee grounds
• Baby wipes, including products marketed as "flushable"
• Feminine hygiene products
• Dental floss
• Diapers
• Paper towels
• Cigarette butts
• Cat litter
• Paints and solvents
• Gasoline and antifreeze
• Pesticides
• Pharmaceuticals
• Large quantities of harsh chemicals

Garbage disposal use should also be limited. Garbage disposals increase the amount of solids entering the septic tank and can increase the frequency at which pumping is necessary.

A simple rule is useful: the toilet should generally receive only human waste and toilet paper, and the sink should not be used for disposing of grease, chemicals, or solid waste.

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4. Protect the Septic Tank and Drainfield

The drainfield is a critical component of the septic system. Wastewater leaving the septic tank is distributed through the drainfield, where the surrounding soil provides additional treatment before the water moves farther into the environment.

The drainfield must remain capable of absorbing wastewater and exchanging air with the surrounding environment.

To protect the tank and drainfield:

• Do not drive or park vehicles or heavy equipment over them.
• Avoid allowing livestock to repeatedly travel over the area.
• Do not construct buildings, decks, patios, or other structures over the system.
• Do not cover the drainfield with asphalt, concrete, or other impermeable materials.
• Maintain appropriate vegetation, generally grass or shallow-rooted ground cover.
• Keep trees and large shrubs far enough away that roots are unlikely to damage or obstruct system components.
• Do not apply unnecessary fertilizers or manure over the drainfield.
• Do not establish a vegetable garden over the drainfield.

Vehicle traffic and other heavy loads can compact the soil and damage buried components. Deep-rooted vegetation can infiltrate piping, while impermeable surfaces can interfere with evaporation and normal soil conditions.

Homeowners should also know the approximate locations of the septic tank, distribution components, and drainfieldso these areas can be protected during landscaping, construction, and other property improvements.

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5. Plumbing Leaks Can Affect Septic System Performance

A plumbing leak does more than waste water when a home uses a septic system. All of that additional water must be processed by the septic tank and drainfield.

A continuously running toilet can waste a substantial amount of water each day. Even smaller leaks from faucets and plumbing fixtures can add significant amounts of unnecessary wastewater over time.

Excessive water entering the system can:

• Reduce settling time within the septic tank.
• Increase the potential for solids to leave the tank.
• Hydraulically overload the drainfield.
• Keep drainfield soils excessively wet.
• Reduce the system's ability to properly treat wastewater.

Running toilets, leaking faucets, malfunctioning water softeners, and other sources of continuous water discharge should therefore be repaired promptly.

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Know the Warning Signs of a Septic Problem

Homeowners should also recognize conditions that may indicate a developing septic problem. Warning signs can include:

• Slow-draining plumbing fixtures throughout the home
• Gurgling drains or toilets
• Sewage odors inside or outside the home
• Sewage backing up into plumbing fixtures
• Unusually wet or soggy soil around the drainfield
• Standing water over the septic system
• Unusually lush or rapidly growing vegetation over portions of the drainfield
• Septic alarms activating on systems equipped with pumps or controls

These conditions should be evaluated promptly by a qualified septic professional.

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Proper Maintenance Protects the Property and Groundwater

A properly functioning septic system treats wastewater on-site before it returns to the surrounding environment. A malfunctioning system can release inadequately treated wastewater containing bacteria, viruses, nutrients, and other contaminants into the soil or groundwater.

For Montana homeowners with private septic systems, the most important practices are straightforward: pump and inspect the system when necessary, manage water use, control what enters the drains, protect the drainfield, repair plumbing leaks promptly, and address warning signs before they become major failures.

With appropriate maintenance, a conventional septic system can provide reliable wastewater treatment for many years.

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