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Septic System Maintenance Tips: A Home Inspector’s Guide to Onsite Wastewater Management

Written by Mike S. Avelar, CPI

Onsite wastewater systems are common in rural areas and even some city limits where municipal sewer connections are unavailable or costly. Understanding how these systems work — and how to maintain them — is essential for protecting your home, your health, and the environment.

This guide covers everything homeowners need to know about septic systems, wastewater treatment, absorption fields, alternative systems, and signs of failure. These septic system maintenance tips will help you keep your system functioning safely and efficiently.

What Is a Septic System?

A septic system is an onsite wastewater treatment system consisting of a buried tank and an absorption field. Tanks are commonly made of:

  • concrete
  • steel
  • fiberglass
  • polyethylene
  • other approved materials

Most tanks hold around 4,500 litres (1,000 US gallons) or more.

Proper maintenance is critical. Without it, septic systems can pose serious health risks.

Diseases linked to improper wastewater handling include:

More information: Enteric disease — A major health concern in Canada

A historical example of wastewater contamination is the 1854 Broad Street cholera outbreak, where Dr. John Snow discovered that drinking water was contaminated due to improper waste disposal.

Goals of Wastewater Treatment

Whether your wastewater goes to a municipal plant or a private septic system, the treatment process must ensure:

  • Potable water supplies are protected
  • Direct human exposure is prevented
  • Waste is inaccessible to insects, rodents, and other vectors
  • Environmental regulations are followed
  • Odors and nuisances are minimized

Raw sewage is mostly water with about 0.1% impurities, including organic materials and pathogens. Treatment removes these impurities before releasing effluent into soil or waterways.

Types of Wastewater Treatment Systems

Centralized Treatment Plants

Large facilities that process millions of litres per day.

Onsite Treatment Systems
  • septic tanks
  • absorption fields
  • combinations of both
Stabilization Ponds

Used for smaller populations or areas with marginal soil and ample land.

Water-Carrying vs. Non-Water-Carrying Systems
  • Water-carrying: septic tanks, sewer systems
  • Non-water-carrying: privies, composting toilets

How Wastewater Decomposes

Two biological processes break down wastewater:

Anaerobic (no oxygen)
  • faster decomposition
  • fewer odors
  • used in septic tanks
Aerobic (oxygen required)
  • used in most municipal treatment plants
  • also used in advanced onsite systems

Most septic tanks use both processes.

Septic Tank Systems

Septic systems require regular maintenance and eventual repair or replacement. A typical system includes:

  • septic tank
  • distribution box
  • absorption field (leach field)
Tank Functions
  1. Sedimentation of solids
  2. Storage of solid waste
  3. Anaerobic breakdown of organic materials
Placement Requirements

Minimum distances (may vary by region):

  • 10 ft from the house
  • 5 ft from property lines
  • 50 ft from wells
  • 25 ft from streams

Always check local health authorities for regional requirements.

Aerobic Septic Systems

Aerobic systems use oxygen to treat wastewater more aggressively. They:

  • remove suspended solids
  • reduce pathogens
  • may nitrify ammonia
  • operate as continuous or batch flow systems

These systems are ideal where space is limited or soil conditions are poor. They require regular maintenance and may include pumps, alarms, and pretreatment units.

Sludge and Scum Management

Inside the tank:

  • Sludge settles at the bottom
  • Scum floats on the surface

Both must be monitored through the inspection port.

Why this matters
  • Excess sludge can damage the absorption field
  • Scum entering the outlet can clog the field
  • Cold climates (like Ottawa) cause faster buildup

Ignoring sludge and scum levels leads to expensive repairs.

Absorption Fields (Leach Fields)

Absorption fields treat effluent after it leaves the tank. Before installation, the site must be evaluated by:

  • environmental health specialists
  • soil experts
  • qualified contractors
Factors affecting placement
  • topography
  • soil texture and structure
  • drainage
  • depth to restrictive layers
  • available usable area
 

Absorption Field Trenches

The most common system on level land.

How they work
  • Effluent flows from the tank → distribution box → perforated pipes
  • Pipes sit in gravel-filled trenches
  • Effluent seeps into the soil for final treatment
General guidelines
  • trench depth: 18–24 inches
  • at least 12–18 inches of acceptable soil below
  • trench bottom may be up to 4 ft above groundwater
  • pipes should be level
  • distribution box pipes ≤ 100 ft

  • serpentine systems may be hundreds of feet long

Trenches are covered with geotextile or biodegradable material to prevent soil intrusion.

Monitoring Ports

Installed to measure liquid depth and evaluate system performance.

Alternative Septic Systems

As land becomes more expensive and soil conditions worsen, alternative systems are increasingly used.

Mound Systems

Used where groundwater, bedrock, or clay are close to the surface.

How they work
  • sand fill is placed over native soil
  • effluent is pumped upward into the mound
  • pump chamber uses float switches
  • alarms notify homeowners of pump failure
Advantages
  • works in poor soil
  • efficient land use
  • resistant to household chemicals
Disadvantages
  • requires level lots
  • expensive
  • needs regular flushing
  • must be carefully designed

Low-Pressure Pipe (LPP) Systems

Used in shallow soil profiles.

How they work
  • effluent pumped through laterals with small holes
  • dosing occurs once or twice daily
  • alarms monitor pump failure
Advantages
  • uses 50% less space
  • works in irregular lot shapes
  • preserves natural site conditions
Disadvantages
  • electrical components
  • requires regular maintenance
  • complex installation

Constructed Wetlands (Plant-Rock Filter Systems)

A natural‑style treatment system using rock filters and vegetation.

Advantages
  • uses 33% less space
  • works in shallow water tables

  • low maintenance

Disadvantages
  • installation cost varies
  • effluent must be disinfected
  • limited installer availability
  • lifespan uncertain

  • some homeowners find them unattractive

Septic System Dos and Don’ts

Do:
  • conserve water
  • fix leaks
  • run full loads of laundry/dishwashing
  • monitor sludge and scum levels
Do NOT:
  • run water continuously
  • install a garbage disposal
  • flush chemicals, sanitary products, tissues, cigarette butts
  • pour grease, oil, pesticides, cat litter, coffee grounds
  • use septic additives or cleaners
  • take long showers excessively

Signs of Septic System Problems

Watch for:

  • sewage backing up
  • slow drains
  • wastewater pooling on the surface
  • lush green grass over the field
  • nitrates or bacteria in well water
  • algae blooms in nearby ponds
  • sewer odors indoors or outdoors

If you notice any of these signs, contact a Septic System Specialist immediately.

Final Thoughts

Septic systems are reliable when properly maintained. These septic system maintenance tips will help protect your home, your health, and your environment. Regular inspections, proper water use, and timely repairs are essential for long‑term system performance.

Thanks for reading! And thank you to InterNACHI® for the excellent training materials and images referenced in this article.