18 Common Septic System Problems & How to Fix Them


  Let's get them sorted, shall we? 

18 Common Septic Tank Problems & How To Fix Them

It's no secret that septic systems can be a bit tricky and frustrating to live with at times... And we know first-hand that when septic tank problems strike, you want to get them fixed FAST!

Whether you're new to septic care and maintenance; or noticing some septic system problems you haven't encountered before - rest assured. We'll not only help you diagnose the cause of your hassles, but show you how to fix them while saving yourself thousands in the process.

In this guide, we’ll run through the main issues that might “come to a head” at your place, and tackle the solutions you need to restore your septic system to full working order:

Topics Covered in this Guide


Before we get down to business, it helps to have an understanding of your system’s basic functions so you know what’s normal and what’s not.

While every septic system is a bit different based on their various tank sizes and field configurations; the basic principles of all anaerobic septic tanks are the same: Relying on a system of good bacteria to break down wastewater in the tank, convert it into non-pathogenic composted material, then expel it back into nature.

How septic systems work

1. Collect Waste

In your home, all the drain pipes from your toilet, shower, sinks and washing machine funnel down to an underground septic tank buried outside. From here, beneficial bacteria in the chambers digest the solids and wastewater, breaking it down into layers.

2. Digest Layers

Next, heavier particles sink to the bottom of the tank, while fats and oils form a layer on top. Once these sludge and scum layers have been digested and separated, you’re left with nutrient-rich effluent liquid.

3. Disperse Effluent

Finally, this safe, non-pathogenic liquid is discharged from the septic tank, entering a drainage system of perforated pipes buried in your leachfield. This allows the effluent to be slowly released into the soil, where it absorbs into the earth and provides an excellent fertilizer for your lawn!

Sounds simple, right? The design and process of septic tanks is beautifully basic… But what about when they don’t work properly?

Don’t worry - There’s just a few things you need to do as a homeowner to keep things running smoothly in your septic system, and we’ll cover them all below. Let’s start with some troubleshooting!


If there’s a problem in your system, you may notice a host of unpleasant symptoms such as foul odors, slow drains, gurgling sounds in your plumbing, backups in your toilet, and even puddles on your lawn.

Septic failures are usually easy to identify, as they can really impact your home life… Septic problems stink! 


Believe it or not, the #1 cause of septic system failure is a lack of consistent maintenance.

Although the biological processes happening inside your tank are astounding, they do need a little helping hand to keep your system performing optimally. This ensures the sludge won’t get out of control, grease cap won’t take hold, and the biomass of hardworking bacteria keep doing their tough job of digesting the waste.

Now, I know what you’re thinking... But before you assume “consistent maintenance” means calling in the professionals, you’ll be pleased to hear there’s an alternative to expensive service calls that not only renders better results, but actually supercharges your septic tank in the process.

(I bet the pump-out guy didn’t tell you your routine septic maintenance could be as simple as flushing your toilet 3 times!)

Even though septic systems are common in America, it doesn’t mean they’re well understood. And the biggest misconception most people have is needing to pay professionals to take care of business that will sort itself out if you just help Mother Nature along a bit…

THE FIX: Great news... With a fast, effective DOWN JOHN™ Treatment, you can put all your septic headaches behind you!

This innovative biological additive does all the dirty work for you, thanks to its proprietary formula that treats, protects & supercharges your septic system.

Scientifically developed for convenience and cost-effectiveness, this simple Flush 'n' Go treatment eliminates your need for inspections and having your tank pumped out - Not only treating existing problems, but preventing their return.

The technology behind DOWN JOHN™ works in 3 powerful ways:

  First, it dissolves grease cap and prevents it from blocking up your system & plumbing.

  Next, it boosts the growth of healthy bacteria in your tank so they combat odors & efficiently break down organic waste.

  Finally, it works as a shield of armor to protect the bacteria in your septic tank from detergents, chemicals & medicines that wash down into your system.

The best part? You only need to apply it once a year by flushing it down your john - it couldn’t be easier!

As our gift to you, here's a little something to help end your septic struggles:


It pays to keep an eye out for the first signs of trouble so you can act swiftly. While these annoying symptoms might just seem like a minor nuisance at the time, they can cause serious damage to your system if left unchecked.

To avoid costly repairs and troubleshooting efforts, early detection is everything!

Here’s the top 6 warning signs of septic system failure to watch out for:

6. Nasty Odors

Notice any rotten egg or sewage smells wafting out of your drains? This usually means your tank’s bacteria colony has dwindled and is no longer digesting waste effectively or consuming the noxious gasses being released.

For the fastest, most effective odor treatment, simply top up your tank with DOWN JOHN™ and bust those foul odors!

5. Slow Drains

Drains that take a long time to empty in your sinks, shower or tub could point to a blockage in your inlet pipes that lead from your house to your septic tank. This is often caused by a buildup of hair, body oil and soap scum that washes down in the shower and solidifies in your pipes. 

Don't forget: Regular clog-dissolving drain cleaners are NOT septic-friendly! To keep your tank healthy, try our custom-blended DOWN JOHN™ Grease Gobbler treatment.

To order, simply contact us with your tank size, type, and a description of your issue. We'll formulate a customized dose specially tailored for your system, that's guaranteed to clear your pipes without harming your septic tank! Click here to request yours now. 

4. Backed-Up Toilets & Wastewater Coming Up Into Drains

Wastewater and toilet backups can be caused by several issues, but predominantly an overloaded tank or drain field is to blame.

Once you’ve ruled out a clog caused by non-biodegradables or sanitary items, try accelerating your tank’s waste digestion rate with a quick and easy DOWN JOHN™ treatment to speed things along.

3. Gurgling Sounds in Your Plumbing System

Gurgling noises in your pipes, toilets, or sinks suggest an underlying issue like a clog in your inlet line or drain field fails.

2. Drainfield Failure

Mushy, wet patches collecting on the surface of your lawn suggest your tank can’t keep up with peak digestion rates, causing your tank to overfill. This also occurs when bacteria is out of balance and excess biomat clogs your gravel pit, blocking the drainfield pipe system.

Luckily, DOWN JOHN™ also digests sludge in your drainfield soil, improving percolation and reversing biomat buildup.

1. Well Water Testing Shows High Levels of Coliform or Nitrates

If your property’s water supply comes from a well, you’ll know the importance of regular water quality testing. If tests detect increased levels of nitrates or coliform (the family of E. Coli) bacteria are present, wastewater from a septic system failure may have leached into your well and contaminated your water source.

Give your family and community peace of mind by treating your system with DOWN JOHN™ - once treated, wells test negative for both nitrates and coliform bacteria.


Common failures of septic systems include clogs, blockages, plumbing backups, leachfields that fail to evenly disperse effluent, and sluggish waste digestion rates that lead to a variety of other unpleasant symptoms.

Below, we'll explore some of the main reasons why your system might be failing...


Septic tank failure can also occur as a result of real-life factors that are tough to avoid, even if you’re keeping on top of your routine maintenance. These include the use of harsh chemicals, visitors increasing your water usage, pesky tree roots, and more. But don’t worry, there are some work-arounds if you know what to look for!

Check out these strange factors that may be the underlying problem at your place, plus our tips on how to address and prevent them:

7. Use of Harmful Cleaning Products

Almost all the cleaning products we use in our homes contain harsh chemicals - and most of them end up going down the drain!

Cleaning products such as bleach, soap, laundry detergent, dishwasher tablets, and toilet cleaners all kill the good bacteria in your tank, destroying the microcosmic ecosystem that breaks down the sewage.

Additionally, you may also have various pharmaceuticals going down your john, plus antibiotics that are still active after being excreted in urine. Naturally, all these aggressors spell disaster for your live bacteria.

This becomes a major septic tank problem because without any good bacteria processing the waste, it quickly builds up on the bottom of your tank, causing it to fester and rot. Once that happens, gasses are released. Cue the foul odors wafting up through your drains into your house and yard - yuck!  

THE FIX: Avoiding cleaning products entirely is simply not practical, but there is an easy solution! You can protect the beneficial bacteria in your septic tank with an annual DOWN JOHN™ Septic Treatment.

Through its activated carbon component, DOWN JOHN™ binds and removes harmful chemicals & pharmaceuticals that normally kill off important septic tank bacteria, then continues working for a full year so you’ll never have to give up your favorite cleaning products.

6. Increased Water Usage 

If your household uses more water than your tank is designed to handle, hydraulic overloads can occur. This septic system problem happens if too much water is sent down your drain pipes in a short time, flooding your leach field and waterlogging the soil before it’s had a chance to absorb it.

Additionally, if your drain field gets too wet, the bacteria in your tank can’t break down organic matter fast enough. This can cause an overgrowth of biomat - the slimy substance surrounding your underground leach pipes that filters out pathogens in the outflow liquid and regulates its rate of absorption into the soil.

Subsequently, you could be looking at ponding on your lawn at best, and wastewater backups coming up your drains in extreme cases.

THE FIX: To prevent excess water flooding your septic system and waterlogging your drainfield, a simple DOWN JOHN™Treatment does the trick!

After application, bacteria numbers begin self-regulating & increasing their colony size to match your input. This prevents overloads and flooding, making it the ideal solution for when family visits to avoid spacing out showers or spreading laundry cycles out over several days.

It’s even powerful enough to cope with increased demands at event centers, churches, Bed & Breakfasts and businesses with frequent bathroom visitors!

5. Tree Roots Infiltrating Your Pipes

If you’ve got big trees on your property or nearby, there’s a chance plant roots could encroach on your septic system. This can cause a lot of damage by either penetrating the pipes leading from your house or cracking the tank walls.

If roots infiltrate your underground system, you’ll notice a foul smell in the air outside as untreated septic tank contents leak out into the dirt. 

THE SOLUTION: This is a tough one to predict as you’ll never know how far or wide tree roots might spread. For existing homes with established gardens, it’s worth getting a professional to inspect your property and identify any trees at risk of breaching your tank with their roots.

They may recommend installing root barriers or using copper sulfate on certain trees to stunt root growth - but avoid using root killer as that also kills the bacteria in your tank!

If you’re planting a new garden, allow plenty of space around your septic and choose shallow-rooted tree species with less aggressive roots.

4. Inlet Baffle is Blocked

In order to pass down into your septic tank, sewage from your home’s pipes must funnel through an inlet baffle opening. This device controls where the flow of liquid lands inside your tank to avoid disturbing the scum layer, and prevents any solids from coming back up into your house if you have a backup.

If wastewater backs up or your drains are moving slowly, you’ll know you’ve got a blockage at this junction.

THE SOLUTION: If you're able to access the inlet baffle opening yourself, you can inspect it and remove any toilet paper, household waste, or other debris you find clogging the pipe by carefully poking around with a pole.

To prevent future blockages, be sure to only flush human waste and toilet paper (Anything cellulose-based is ok, but feminine products will not be easily digested). If in doubt, call a professional to take a look!

3. Outlet Baffle is Clogged

Before effluent flows out of your tank and into the leachfield, it must first pass through an outlet baffle. This device prevents any solids from escaping out into the leach pipes, which could clog up or destroy your whole leach field system - potentially costing thousands to dig up and replace.

Watch out for sewage backing up into your home or pooling on the surface near your septic tank to alert you to an outlet baffle blockage.

THE SOLUTION: Call a professional for an inspection immediately if you notice the above warning signs, or you might be looking at a costly drain field repair!

If your tank has an effluent filter, it will also need to be cleaned or replaced. Blockages can be prevented in the future by cleaning your effluent filter and avoiding hydraulic overloads.  

2. Your Tank Was Not Installed Properly

Unfortunately, human error can come into play when installing a septic system, and there’s a chance your tank may have been built on unsuitable ground with an excessive slope or the wrong soil type.

Alarmingly, aside from the potential problems you could face if your tank was incorrectly installed, you could also be vulnerable to legal implications if your setup is not in compliance with local regulations.

THE SOLUTION: An installer should first ensure your property is suitable for a leach field system by running a percolation test, which shows how well the ground will drain in the chosen part of your property.

If you purchase a home with an existing septic system out of compliance, you may need to replace the entire system. To protect yourself from such hardships, be sure to understand the laws in your area and conduct any tests before closing on any property purchase.

1. Your Tank is Very Old

All good things must come to an end - including the usable life of any septic tank! With proper maintenance, you can expect a good 20-30 years on average out of your tank, provided it was installed correctly, not overloaded, and built well. 

THE HONEST TRUTH: When you consider all the dirty work your tank’s been doing since it was installed, that’s a pretty good run in our opinion! When it’s time for a new system, it’s time...


As important as a well-functioning septic tank is to the whole process, drainfield fails are equally critical.

Stay vigilant so you can act fast if you notice any symptoms of failure in your leach field - Your speedy action to remedy these problems could mean the difference between a quick treatment, and needing to dig up your entire yard!

Watch out for these 5 telltale signs of trouble with your drainfield:

5. Septic System Backup

If water in your tank rises up high enough to push sewage back up the inlet pipe, through your plumbing fixtures, and into your home's lowest drains; it could mean a blockage in your biomat is preventing effluent from flowing away into the ground.

Apply DOWN JOHN™ to regulate biomat levels, which helps the gravel evenly drain away treated outflow runoff and improve your leachfield percolation.

4. Foul Odors Near Leach Field or Septic Tank

Take a walk over your leaching field every couple of weeks so you can promptly sniff out any unpleasant odors. You shouldn’t detect even a whiff of sewage smell being pumped into the air, so addressing clogged pipes promptly when they first start releasing odors helps avoid bigger problems down the line.

If application of DOWN JOHN™ doesn’t tackle smells within a few weeks and return your drainfield to proper operation, you may have a more serious issue like cracked pipes or a fractured tank on your hands. Give your local contractor a shout to come and see what’s up.

3. Lush, Bright Green Grass Above Drainfield

Is the grass over or around your septic greener than the rest of your lawn? If you notice a patch of lush, bright grass or accelerated plant and weed growth above your leachfield, you might have a pipe malfunction down below.

As much as we love a thriving garden, in this case it’s a red flag you shouldn’t ignore. It suggests decomposing organic matter has escaped from your tank or part of your field has leaked too fast, expelling excess nutrients into the dirt that act as a fertilizer.

 2. Puddles or Standing Water Near Drainfield

When you do laundry or several people in your household take a shower in quick succession, do you notice a wet spot appearing in your yard? Standing water on the lawn could indicate several problems that may need diagnosis by a licensed professional.

You may be looking at overly compact earth that’s not absorbing properly due to the wrong type of dirt, or has become compressed by heavy storms. This issue is quite common after heavy rain, so if you think that might be the cause, try waiting a while for things to dry out and see what’s next.

Don’t forget, you may even have crushed leach pipes due to vehicles parking on top of your field, heavy machinery damage, or ground movement applying excess pressure on your system.

1. Blooms of Algae in Ponds Near Your Leach Field

If your property has a pond or lake nearby, be sure to keep an eye out for sudden algal blooms appearing on the surface. While a little algae is normal on natural bodies of water, an excessive amount appearing out of nowhere could mean your drainfield isn’t absorbing effluent effectively and is leaching nitrogen to surrounding areas.

Don’t forget, leach field problems should be treated swiftly. If in doubt, be sure to call your local plumber to give your setup a full inspection. If they notice any loss in drainage capacity, they’ll be able to lay out your options for fixing the problem before the system completely stops processing waste. 


Septic systems allow sewage to be released into the ground safely - so when they don’t function properly, pathogenic wastewater is released into the environment and surrounding areas. This contaminated water can even find its way into other water sources, posing a serious health hazard to people and animals alike by making the water unsuitable to drink, swim in, or use for agriculture.

As septic tank owners, it’s our responsibility to ensure the safety of our community by maintaining a well-functioning system that won’t pose a health or environmental risk.

Take charge of your septic system's performance with an annual DOWN JOHN™ Treatment. This highly effective technology tackles most common septic system problems before they begin, and will remedy any present symptoms you’re noticing.

The #1 solution for your #2s... In just 3 easy flushes!

get yours here

This quick, cost-effective treatment will save you thousands in repairs, inspections and pump-outs. Want to learn more about how it works and the easy steps to apply it? Check out our Ultimate Guide to DOWN JOHN for all the intel you need to tackle septic issues with ease.


Septic tank and drain field replacement can be a costly affair, with the average price of a new 1,000 gallon septic tank ranging from $1,500 to $5,000.

It only gets worse if you need a new drain field too. This could set you back around $3,000 to $15,000 on top of that, with the price varying depending on factors such as the size of your drainfield, its location, the slope of your property, type of soils, and accessibility in your yard. Yikes!

As you can imagine, it’s best to avoid any potential financial shocks by maintaining your existing system with an annual care plan. Luckily, this is actually super cheap, fast and easy to do with DOWN JOHN! We've helped thousands of happy customers save on repairs, call-outs and tank replacements with this smart, preventative treatment system.

How to Prevent Many Common Septic Tank Problems

As with most things in life, prevention is better than a cure. Fortunately, many common septic system problems can be avoided with a simple once-a-year DOWN JOHN™ treatment.

Unlike many other septic tank treatments on the market, DOWN JOHN™ doesn’t just treat existing issues like odors, sludge, grease cap & leachfield clogs...

It also nourishes and protects the biomass in your tank which prevents issues from returning.

Its powerful combination of active ingredients keep working in your tank for a full year, making it the most hassle-free, easy-to-apply, and budget-friendly treatment you can choose.

All you need to do is flush three simple packs down your toilet once a year - no special tools or skills required! It's as easy as 1,2,3...

To save $10 off your first DOWN JOHN™ Treatment kit, subscribe below to receive your secret discount code & make your septic struggles a thing of the past!


We're here to help.

Still have a few questions? No worries! After 18 years in the business, we understand that septic maintenance can be a challenge - especially if you don't have the right stuff in your toolkit yet…

Whether you need some expert advice on what to do at your place, or you have questions about the DOWN JOHN™ treatment system - We've got your back and we're here to support you.

Feel free to reach out to us at info@downjohn.com or give us a call during business hours on 888-529-9001.  We'd love to hear from you. 

Annual Septic Tank Treatment

DOWN JOHN™ is a revolutionary 3-part treatment for anaerobic septic systems.
Quick, easy, and cost effective - One annual treatment keeps your septic running smoothly & performing optimally for a whole year!
Effectively restore your septic system & provide sustained environmental benefits with this innovative treatment kit below: