Septic Tank Treatment: What Works and What Doesn't

The septic tank smell problems can be as frightening as having your home turn on you. Things appear normal one moment and you smell “rotten eggs” in your bath room, or that strange yard odor appears the next.

Worry starts to creep into your mind regarding cost for repair, the health of your family, and so much more. Your fears are valid and you’re certainly not the only one with these same concerns.

This guide will walk you through all of the safe, simple checks and quick fixes you should attempt first, prior to spending a great deal of money on a professional visit. You will also learn what most of those smells signify, what you can do immediately to resolve them, and at what point you need to seek assistance.

What Causes a Septic System to Smell in the First Place?

An offensive septic tank smell problems can be alarming and seem as though something in your home is attacking you; however, in most cases, there will be a common, identifiable cause for the smell that can easily be remedied once you identify the source of the odor and understand what it typically signifies. Once you have an understanding of where the smell originates and what it generally indicates, you will no longer think about the worst-case scenario, become less anxious, and take easy and logical steps to address the issue.

Normal septic tank gases vs real smell problems

It’s perfectly fine for every septic system to create gas, because this is just how it operates. When bacteria digest your household waste within your tank, they convert all that waste into gases (like):

• Methane – a flammable gas with no scent by itself
• Carbon dioxide – that you exhale yourself too.
• Hydrogen sulfide – the classic stinky smell of a rotten egg.

When everything is working as it should, those gases will remain contained in your piping and tank; and they’ll naturally dissipate through your vent pipe on top of your house.

You shouldn’t be able to smell those gases inside your house. And occasionally, you may catch a whiff of a faint odor when opening the tank cover.

However, if you consistently have very strong and continuous smells in your home, around your drains, or throughout your yard, there’s clearly an issue with your system. A portion of your septic system isn’t performing its duties properly, and the gas is finding a way into your living space.

If you suspect your tank itself is too full, you might want to look at a DIY septic tank cleaning guide so you know what to expect when someone pumps it.

Clogged or dry P-traps and drains inside your home

P-traps are U-shaped pipes located underneath kitchen sinks, as well as beneath the floor drain at laundry rooms. P-traps have a small reservoir of water that acts as an airlock by preventing sewer gas from rising back through the pipe.

Over time, if a drain goes unused for weeks (or longer) the water in the p-trap will eventually evaporate. When this occurs, there is no barrier to prevent septic gases from entering the space above the drain. It is also why many people find their basement shower,

guest bathroom sink or laundry room floor drain will suddenly become smelly.

Hair, grease and soap will eventually clog the trap causing a dirty drain odor. This odor is different from “rotten eggs,” however, when combined with the “rotten egg” odor from septic gases, it can be perceived as being much worse.

Vent pipe problems on the roof

Vent pipes help to balance the pressure within the plumbing system and allow water to flow, so that gases created when sewage is broken down won’t come back into your house. When the vent pipe is clogged with debris or other items, odors will build and be forced back through your drain lines.

Common items that can become lodged in the vent include:

• Debris such as leaves, sticks and branches

• Bird or wasp nests

• Snow and ice that has accumulated on the vent during colder months

When you block one end of a hose with your hand, you’ve essentially prevented the fluid inside the hose from flowing. The same occurs with a clogged vent on your home’s plumbing system. In some cases, water will find its way through your bathroom when the vent pipe is clogged.

Septic tank or drainfield issues in the yard

Typically, an unpleasant septic tank smell problems in your yard will point directly toward either your drainfield or your septic tank.

Possible problems with “outside” factors that would produce those bad smells are:

1. The time has come to pump your septic tank.

2. Your drainfield may be clogged/water-logged.

3. Compacting of your soils due to parking/driving over areas of your drainfield.

4. Prolonged excessive rainfall can make the drainfield so wet that odors rise up.

Some things you might see if there are some issues are:

1. Grass is consistently damp/soggy, regardless of the remainder of the area being dry.

2. Puddles/standing water surrounding your drainfield or septic tank cover.

3. A strip of grass in the area you discharge your septic system appears to be exceptionally green/vibrant/thick.

These septic tank smell problems symptoms are indicative that waste water is not draining down into the earth as it should. These are not just “bad smells,” these are signs that your system needs the attention of a professional

Check sinks, showers, and floor drains for dry P-traps

Begin with the areas of your home that you typically do not use (e.g., guest bathrooms) and go through the house room-by-room.

1. Turn on the water in all sinks, showers, and bathtubs for 30 to 60 seconds.
2. Put water down all floor drains that are located in basements, laundry rooms, or garages.
3. Check the area around each drain for a smell one to two minutes later.

If a drain has a much stronger smell immediately after running water, it was probably a dry P-trap. Use a cup of water and add one tablespoon of mineral oil to the cup to put in floor drains that you don’t frequently use. Mineral oil floats on top of the water and will help slow the evaporation process; therefore, the trap will be full for a longer time.

Here is a simple reference guide to some of the most common smelling drains and how to temporarily solve them.

Area: Guest Bathroom Sink

Common Sign: A slight sour or musty smell

Easy Fix: Let the water run for approximately one minute.

Area: Basement Shower
Common Sign: A strong rotten egg or sewer smell

Easy Fix: Run the shower for 1-2 minutes and close the door for approximately one hour.

Area: Laundry Room Floor Drain
Common Sign: A very strong odor near the floor

Easy Fix: Slowly pour 1-2 gallons of clean water into the drain.

Area: Garage or utility room floor drain
Common Sign: A strong smell near the water heater or furnace.

Easy Fix: Pour a bucket of water into the drain.

Area: Rarely used tub
Common Sign: A light sewer smell when you enter the room

Easy Fix: Turn on hot water in the tub for several minutes.

Go through your home and try these steps room by room. Dry P-traps may quickly lose their ability to seal off septic tank smell problems once they are refilled.

Wait a few hours after you refill each P-trap. If the smell goes away, you may have found at least a portion of the source of the odor.

If the smell returns within a couple days of refilling the P-trap, you may have a different type of problem (such as a vent issue or a clog further along in the pipe).

Clear light clogs and gunk in smelly drains

If your drains are running slow, or if there is a thick build-up on them, then there could be an unattractive film on the inside wall of the pipes. This film will start to rot and emit a foul odour.

There is a simple method to address this issue, without using harsh chemicals:

1. Turn the cold and/or hot tap (whichever is available) on full and allow to run for 1 to 2 minutes.
2. Add 1/2 cup of Baking Soda.
3. Slowly pour in 1 cup of White Vinegar, allowing it to fizz and bubble for 10 to 15 minutes.
4. Rinse with scalding hot water for another 1 to 2 minutes.

You may use this solution on your sink(s), shower(s), or bathtub(s) that smell sour, oily/greasy, or “like dirty socks”. It will not solve true septic gas problems by itself; however, it often eliminates the nasty drain odour that combines with these other odours.

Unless a licensed plumber directs you to do otherwise, DO NOT pour strong chemical drain cleaners into your septic system. Many drain cleaners contain chemicals that will kill off the beneficial bacteria within your septic tank.

Check the roof vent pipe for blockages for Septic Tank Smell Problems

If you are still smelling septic gases in your home even after adding water to your drains, then it’s possible that the vent pipe on the roof of your house is clogged.

Here are some common indicators from the ground that there may be an issue:

Look at your roof:

Inspect the roof to find any issues with the vent pipe.

Look for any obvious debris such as bird nests, leaves, etc.

Winter months can cause additional problems due to snow/ice accumulation on the vent pipe.

If you feel comfortable climbing on a ladder, here are some things you can do from the roof:

Use a flashlight and/or a small mirror to inspect the area.

Peek directly into the vent.

Using gloves and/or a grabber tool, remove any loose debris.

Use a garden hose with very little pressure to “flush” a light clog.

Do Not Blast High Pressure Water or Stiff Tools Down the Vent Pipe. This can damage the pipe or move the clog further up the pipe.

If you see a solid clog you can’t get to or are uncomfortable climbing on the roof, stop and Call a Plumber. A Professional can usually resolve this type of problem quickly and will eliminate the septic gas odor.

Look for simple issues around toilets

There are many ways to get septic tank smell problems in your house from toilets, even if you don’t see a leak there could be a small gap between pieces or the parts on your toilet are loose allowing gases to escape.

Here is a simple way to check each toilet:

1. Rock the toilet gently at its base.
2. If the toilet will move slightly then the mounting bolts probably are loose.
3. Look closely at the area around the base of the toilet and behind the tank. If you find any sulfurous or sewer smell.
4. Check for dampness or stains on the floor surrounding the base of the toilet.

If the toilet does move, loosen (do not overtighten) the bolts at the bottom of the toilet a little bit at a time one bolt at a time.

If you still smell sewer gas or see staining around the base of the toilet after tightening the bolts, the wax ring is likely failing. A plumber can replace the seal in about an hour. The cost is typically much less than calling a septic service company and most times will stop your strong bathroom odor.

Quick checks outside near the septic tank and drainfield

Go outside if the worst smelling area is outside.

Look up in the yard where the tank and drain field are located and look for:

• Wet, soggy patches in the yard, but the rest of the yard is dry.

• Puddles of standing water by the tank lid or distribution box.

• A band of grass that is green and thick and different from the rest of the yard.

• Strong sewer or sulfur smell when it is still (not windy).

Some things you can do immediately:

• Keep all large equipment such as cars, trailers, etc. off of your septic tank and drain field; the extra weight will compact the soil and may break the pipe under your house.

• Fix the gutter downspout so they are not dumping water onto the drain field, run them away from the area.

• Do not run lots of water at one time, i.e., do not wash a bunch of clothes and then run them through the washer again, spread this type of usage throughout the week.

• If the outside smells bad and/or there are constantly wet spots, contact a septic professional to check the condition of your septic system. Although these small adjustments may place some lessened stress on your system while you wait for a professional to assist you.

Know when a simple fix is not enough

The “quick check” items in this manual deal with the most common issues that are easiest to correct:

• Dry P- traps in less frequently used (ie. guest bath) drains
• A build-up of light grease in sink or shower drains.
• Minor blockages within the vent pipes.
• Worn, loose toilet(s), or a bad seal at the bottom of the toilet bowl.
• Excess water or weight above the drainfield.

If you’ve tried all of the above and still have:

• A heavy, consistent “rotten egg” smell from the sewage system inside or outside the house.
• Backed up sewage coming into tubs, showers or floor drains.
• Gurgling noises from multiple drains as you flush the toilet.
• A combination of odor and slow drainage across the entire home.

It’s time for you to contact a licensed septic service technician or a licensed plumbing service technician.

Using additional aggressive methods to try to fix your system yourself (i.e., snaking underground lines or opening your septic system without proper training) could result in potential danger to you and/or costly damage to your septic system.

Simple habits to prevent future septic smells

Once the septic tank smell problems is gone, a few easy habits can keep it from returning:

• Flush water through the guest bath and floor drain at least one time each month.
• Place a drain strainer on both kitchen & bathroom sinks for catching hair & food.
• Throw grease/oil/coffee grounds into the trash instead of the sink.
• Space-out laundry loads as much as possible over multiple days.
• Empty your septic tank (on the recommended schedule of your local septic service provider) typically every 3-5 years.

By performing these actions you will allow water to flow easily, protect the beneficial bacteria in your septic tank, and also help extend the life of your drainfield.

You can use a simple reminder checklist stored on the refrigerator or in a drawer to perform these fast checks anytime a new smell appears.

Conclusion

Septic Tank Smell Problems seem like emergencies, however most causes are very simple and can be checked safely by yourself. Clogged dry P-traps, minor clogs, venting problems, and loose toilets are some common and normally simple fixes using just a few basic tools and a little bit of your time.

With these easy checks, you should be able to eliminate the odor, protect your system, and avoid an unnecessary service call. If the smell persists, you notice wet spots in your yard, or you begin experiencing back-up, then it is time to have a licensed septic professional come out and inspect your system.