Septic Tank Vent: Functions, Types & Common Problems

A septic system comes with various components which are interconnected and work as one unit. This article focuses on one component; the septic tank, with a special focus on the venting system.

Here, you’ll learn about its uses, how it works, and whether the vent is necessary for every septic system.

What Is A Septic Tank Vent?

To begin with, it’s necessary to establish the use of a vent, what it does, as well as the types. Basically, vents are openings that let air, and gases out of confined spaces. This is exactly what a septic tank does.

As the wastewater (both black and grey wastewater) empties into a septic tank, treatment commences.

The byproducts of waste decomposition or breakdown are gases. Such gases include nitrogen dioxide, carbon dioxide, ammonia, sulfur dioxide, and traces of carbon monoxide.

These gases are harmful gases that must be let out through the vent.

You may only know about the roof vent coming from the septic tank, but the reality is, there are actually three vent types. All three may be connected to your septic system for the efficient discharge of sewer gases and also for equalizing air pressure in drain pipes.

Types of Septic Tank Vents

Septic tank vents are of three types; inlet & outlet vent pipes, roof vent pipes as well as yard-based septic vent pipes. All three types may be hooked up to your septic system.

Let’s discuss how they function shall we?

  • Inlet & Outlet Vent Pipes

Apart from the vital functions of transporting waste into the septic tank and out into the drain field, the inlet and outlet pipes also serve as vents.

Through these pipes, gases are released to the drain field area. These gases flow outward and cannot return through your plumbing system as there are water traps that serve as valves.

  • Roof Vent Pipes

Roof vent pipes are considered primary venting channels because they’re located on the rooftop and serve the main function of releasing sewer gases.

As with other vent types, not only are sewer gases removed but also foul odors are released into the open air.

Now, you may wonder why these vent pipes are located high up the roof. They’re installed in such a manner to enable these gases and odors to easily dissipate.

When they’re too low, your home’s surroundings will be permeated with sewer gas and odors.

These gases are dangerous when inhaled as they could lead to hydrogen sulfide poisoning, irritation of the respiratory tract and eyes, nausea, nervousness, drowsiness, headache, dizziness, and of course foul odor.

  • Yard-Based Vent Pipes

Some septic tank vents are located in the yard. These are mostly located above the drain field and serve to release sewer gas while also equalizing drain pressure when water is displaced by air.

Without all three vent types, septic hardly functions effectively.

If My Septic Tank Vent Safely Lets Out Gases and Odors, Why Do I Still Perceive Strong Odors?

As stated above, a septic tank vent serves to release sewer gases and odors while also regulating or equalizing drain pressure whenever water is displaced by air.

Odors are hardly perceived as they’re released safely via the septic tank vent.

However, there are times when you might begin to perceive sewer odor. This has a characteristic rotten egg smell which signifies the presence of hydrogen sulfide gas.

When you perceive such a smell, it’s a clear sign that your septic system is malfunctioning.

Several reasons can be attributed to such gas leaks. They include clogging of septic tank vents, as well as improperly installed vents. Clogged vent issues tend to be more common.

However, let’s discuss each of these problems as follows;

  • Blockage of Septic Tank Vents

There are times when septic tank vents get clogged. These dedicated sewer gas escape outlets cease to function normally. Now, septic tank vent clogs can be attributed to several things including frozen pipes.

Others include birds nest built within the pipes, dead rodents and birds, leaves, and all sorts of trash.

Clogging of septic tanks is most common when there are overhanging tree branches. Sometimes, fruits and nuts falling from such trees accumulate within pipes resulting in clogs.

When this happens, the free movement of sewer gas is prevented, thus causing all sorts of issues.

You’re likely to perceive awful odors whenever you flush your toilets. Also, there may be the slow movement of drains including gurgling sounds whenever toilets are flushed.

Clogged septic tank vents need to be cleared to avoid worsening the problem.

  • Improperly Installed Vents

A septic tank vent that isn’t properly installed is likely to cause issues. Installation must be performed by an experienced hand. Only licensed septic tank technicians should be called upon for such jobs.

So, what does an improperly installed septic tank vent mean?

Sometimes, instead of installing the vent in such a way that it projects above the roofline, a shoddy installation job may result in vent openings being close to windows.

This is a sure sign of trouble as gases easily escape into homes. The air around such homes is polluted with occupants exposed to dangerous sewer gases.

You’ll need to call a licensed professional to help correct the problem. Depending on how extensive the faulty installation goes, an overhaul of the venting system may be necessary. Every job differs from the other.

So, you’ll need to call for a professional inspection to determine what action(s) to take.

The Higher, the Better

The height of septic tank venting matters a lot. As discussed above, lower vents are likely to cause more discomfort in terms of odor than higher ones.

For better odor control, consider increasing the height of your vent pipe. This ensures that odors are released at higher levels, thus making it less likely to perceive them.

Inspecting Septic Tank Vents

To prevent issues like clogging, septic tank vents should be inspected frequently to get rid of clogs. The aim is to prevent the accumulation of debris or the building of nests within such vents.

Your annual septic system inspection should include the venting components of the system.

Proper septic tank venting is crucial to its smooth operation.

We’ve discussed what it’s about, how it works, and the problems caused when the venting system is clogged.

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