Septic inspections: what to expect and what to ask

An inspection is the single most useful thing you can buy for a septic system. It tells you whether the tank needs pumping, catches broken parts before they cause a failure, and gives you a record that's worth money when you sell. Here's what a proper one involves.

How often

EPA's SepticSmart guidance says a household system should be inspected by a septic service professional at least every three years. Systems with electrical float switches, pumps, or mechanical components should generally be inspected once a year. EPA's malfunction guidance puts the full range at every one to three years depending on the system.

What the inspector should do

• Locate and uncover the tank. If lids are buried, it's worth adding risers so future visits are quicker. Penn State recommends risers and marking the tank's location.
• Measure the sludge and scum layers. EPA says to pump when the bottom of the scum is within 6 inches of the outlet, the top of the sludge is within 12 inches of the outlet, or together they fill 25% or more of the liquid depth.
• Check the inlet and outlet baffles or tees. A missing outlet baffle lets scum flow straight to the drainfield.
• Clean or check the effluent filter, if the tank has one.
• Look for leaks, meaning a water level that's too low or too high.
• Check the drainfield for wet spots, odors, or surfacing effluent. The distribution box may be opened.
• Test pumps, floats, and alarms on systems that have them.

Ask the provider to write the tank’s condition, the layer measurements, and any repairs on the service report.

Inspection versus pumping

These are separate jobs, though one company often does both. Penn State notes that a tank should be pumped through the large central access ports, not the small inspection ports over the baffles. Pumping through the baffle ports can damage the baffles and leave material behind. The contractor should break up the scum and mix the sludge so the tank is emptied fully. Being there while it's done is a good idea.

Records to keep

Keep a folder with:

• the system permit and site drawing from the health department;
• every inspection report, with the sludge and scum measurements;
• every pumping receipt, with the date and gallons removed;
• any repairs and who did them.

After two or three visits, the measurements show your actual accumulation rate. That's better than any rule of thumb, including our pumping calculator.

Questions worth asking

• How full was the tank, and when do you think it will need pumping again?
• Are the baffles and filter in good shape?
• Did you see any sign of drainfield trouble?
• Is there anything about how we use water that's hurting the system?
• Is anything here required to be reported to the county? Some jurisdictions require inspection reports to be filed, especially at the time of sale.

Safety

Never try to inspect the inside of a tank yourself by leaning in or climbing down. Penn State and EPA both warn that septic gases can be deadly. Keep lids secured so children and pets can't fall in.

What a thorough inspection includes

A full inspection typically covers:

1. Locating the tank and drainfield, and uncovering the tank lids or risers.
2. Measuring sludge and scum with a probe. EPA advises pumping when the scum bottom is within 6 inches of the outlet, the sludge top is within 12 inches of the outlet, or the two layers fill more than 25 percent of the liquid depth.
3. Checking for leaks in the tank, and the condition of baffles, the outlet tee and any effluent filter.
4. Running water through the house to confirm wastewater flows freely into the tank and out to the drainfield.
5. Walking the drainfield to look for soggy areas, odors, surfacing effluent or unusually green grass.
6. Checking pumps, floats, alarms and controls on systems that have them.
7. Reviewing records, such as pumping history and permits.

EPA says that when you call a service provider, they will inspect for leaks and examine the scum and sludge layers in your tank. The provider should also note repairs completed and the tank's condition in a service report.

How often

• Typical households: EPA says the average system should be inspected at least every three years by a septic service professional.
• Alternative systems with float switches, pumps or mechanical parts: generally once a year. EPA notes a service contract is important for these systems because of the mechanical parts.
• Before buying or selling a home: always. See buying a house with septic and well.

Preparing for the visit

• Find your records: pumping receipts, permits, the as-built drawing, and past inspection reports.
• Mark the tank location if you know it, or ask the county for the permit drawing. See how to find your septic tank.
• Clear access to lids and risers. Move vehicles, planters or snow.
• Note any symptoms you've noticed, such as slow drains, gurgling or odors.

Questions to ask the inspector

• What are the sludge and scum levels, and when should I pump?
• Are the baffles and outlet tee intact?
• Is there an effluent filter, and when should it be cleaned?
• Did you see any signs of drainfield stress?
• What type of system is this, and what maintenance does it need?
• Is anything not up to current local code?

Keeping the report

EPA recommends keeping maintenance records of work performed on your septic system, and writing down the sludge and scum levels to track when to pump. A simple folder or spreadsheet with dates, levels and repairs makes the next inspection faster and helps when you sell the home.

Key takeaways

• Inspect at least every three years, and alternative systems yearly.
• Expect sludge and scum measurements, a baffle check and a drainfield walk.
• Have records and access ready to save time and money.
• Keep every report, because together they show the history of your system.