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10 Signs Your Septic Tank Is Full

Any property that isn’t connected to the mains sewerage system, whether it’s domestic, commercial, industrial or otherwise, must have an appropriate place to store the waste generated by its human occupants. For most people, this means having a septic tank onsite, which requires regular maintenance and flushing.
A septic tank generally serves two purposes. On the one hand, it holds wastewater and allows bacteria to break it down so that it can be safely discharged into a nearby, specifically designated drainage field. On the other, it provides a temporary storage solution for the solid waste that is produced by a household.
The key word here is temporary. Over time, the solid waste will build up and must be removed. But how do you know when that time arrives? This comprehensive guide will tell you everything you need to know about septic tank drainage, including what it means to have a “full” septic tank, why it’s important to pump it and, most importantly of all, the 10 tell-tale signs which indicate it’s time to tackle the job.
Table of Contents
Definitions of a “full” septic tank
Before getting into the nuts and bolts of how you can tell whether your septic tank is full or not, it’s a good idea to define what that actually means. For clarity’s sake, there are actually three different definitions of what a “full” septic tank consists of:
- Tank at capacity – This is the most common definition and simply means that the wastewater within the tank has reached the maximum level that it can hold. Over time, the tank should drain itself, since the outtake valve will gradually release the effluent into the designated drainage field. However, if the tank is regularly reaching capacity sooner than expected, that might indicate a more serious problem.
- Sludge accumulation – This is a more urgent definition of a full tank and refers to the solid waste (faeces and toilet paper) contained within its confines. This sludge builds up over time and must be periodically pumped away by a certified professional. If that doesn’t happen, there is nowhere for the sludge to go, which will prevent the wastewater from draining as well. Therefore, accumulated sludge must be dealt with as a matter of urgency in order to allow the tank to return to a fully working state.
- Overfilled tank – This is the worst-case scenario created by a combination of the two previous definitions or, in certain cases, by other external factors. If the drainage field becomes saturated, for example, it will no longer accept wastewater discharge, meaning the tank cannot release any of its contents and will become overfilled. Again, this will require the attention of a professional.
What are the signs that your septic tank is full?
Fortunately, when it comes to home maintenance, your property has a certain way of letting you know that it needs attention. A leaky roof will drip before the deluge, a squeaky door hinge cries out for oil and an ill-fitting window will whistle in the wind.
A septic tank is no different and gives out a variety of signs that it requires attention. And, like the other items mentioned above, it’s worthwhile nipping those problems in the bud before they develop into full-blown issues that can be disruptive to your daily life and very expensive to address if left to their own devices.
Here are 10 red flags which indicate your septic tank is clamouring for your attention and requires a visit from a certified professional to restore it to its normal working condition.
1) Overdue pumping
This one isn’t so much of a sign, but it is the first item on the list because it’s the best way to avoid all of the issues that follow. Having a regular maintenance schedule in place and adhering to it will ensure that your septic tank remains in excellent working order and saves you an inordinate amount of money, effort and stress in the long run.
How do you know what a regular maintenance schedule should look like? Unfortunately, there is no one-size-fits-all answer to this question, since your own particular circumstances will dictate how your schedule should look. That includes the size of your household, the size of your tank and the volume of both solid waste and wastewater that the former generates.
As a general rule of thumb, it’s a good idea to have your tank serviced at least once a year. However, for smaller households with larger tanks, a more infrequent pumping may be sufficient. The best course of action is to consult with a septic tank specialist, who can assess your situation and give you professional advice.
2) Standing water around the tank
There are many reasons why you might experience standing water in your garden. Perhaps you accidentally left a hosepipe running, or maybe a sprinkler head was disturbed during a routine lawn mowing job. A more common explanation could be that it has simply rained a great deal in the last few days.
But if you haven’t experienced a period of heavy rainfall recently and other factors aren’t at play, large amounts of standing or pooling water on your premises could indicate that your septic tank has exceeded its capacity. This could happen anywhere in the vicinity of your home, but it is most likely to occur near the tank itself.
If your septic tank is the culprit, an overflow is most likely explained by either a blockage in the drainage system or an accumulation of sludge inside the tank itself. Either way, the problem will require immediate attention and you should contact a qualified professional to undertake tank emptying services as soon as possible.
3) Unpleasant odours
Septic tanks aren’t just responsible for collecting and storing human waste. They’re also a repository for all of the effluent emanating from your home, including the wastewater discharged from your washing machine, dishwasher, shower and kitchen sink, among others. All of those ingredients combined together can make for one very pungent cocktail.
If your septic tank reaches capacity, it’s not only the solid and liquid contents which will have nowhere to go. It will soon become apparent that there’s something in the air – and something very undesirable. The unmistakable stench of raw sewage is one of the clearest warning signs of a full septic tank, so as soon as your nostrils get a whiff of it, it’s time to call in the professionals.
The unpleasant smells will be most noticeable around the tank itself, but it’s likely that they’ll also travel back up through the pipes and emanate from your sinks, toilets and drains, too. And no-one wants that in their house.
4) Gurgling pipework
As well as extraordinary smells, you should also be able to hear when something is amiss in your home. Of course, gurgling pipes in themselves are nothing to be concerned about, since most plumbing systems are partial to conducting their own mini orchestra within the pipework on a daily basis.
However, if you’ve lived in the premises for any stretch of time, your ear should have become attuned to the various melodies played by your taps, toilets and other drainage fixtures. It should also be able to tell when the pipes are playing bum notes, as well. If your pipes are being more sonorous than usual, or if they’re singing a song you’ve never heard before, it could be an indication that something is up.
It should be stressed that even irregular noises from your pipework isn’t a sure-fire sign your septic tank is full, since there are any number of reasons why the gas and water within the pipes might be making a din. Still, unusual sounds are an indication that the problem may lie with your septic tank, especially if you experience them in tandem with any of the other items on this list.
5) Slow draining
We’ve all been there. Whether it’s a kitchen sink with a plughole that never seems to empty or a shower that fills up to your ankles after only a minute or two of use, slow drainage can cause all sorts of headaches around the home.
Again, slow draining issues don’t necessarily indicate that the issue lies with the septic tank. In fact, there are plenty of other, far more common causes of the problem. In kitchens, for example, food scraps, grease and oil can clog the pipes and cause a back-up, while hair and soap particles are frequent blockers in the shower or bath. If you feel comfortable inspecting the pipes yourself, it’s a good idea to eliminate these explanations before you pursue other avenues of investigation.
However, if the pipes above ground look hunky dory and a commercial sink or plughole unblocking agent isn’t yielding results, it may be that your septic tank is to blame. In that case, contracting tank emptying services might be a sensible course of action to get the water flowing once more.
6) Trouble flushing
This issue is linked to the one above, but relates specifically to the WCs in your home. There’s nothing worse than a busted flush. The ability to flush away the contents of your toilet bowl are a modern convenience most households simply cannot do without. With that in mind, it’s no surprise that it’s become an English idiom.
Of course, there are plenty of other reasons why your toilet might be experiencing flushing issues. It could be caused by the idiom mentioned above and that the mechanism itself has been compromised. The pipes might have become clogged by things being accidentally flushed down the toilet when they shouldn’t have been. Or it could even be more serious.
Those fortunate to have one than more bathroom on their premises have an advantage here, since an issue with more than one toilet generally indicates that the problem goes beyond any individual flaws with the unit. Inadequate flushing experienced alongside slow draining (or any of the other issues raised here) could point to the septic tank as the root cause.
7) A suspiciously lush lawn
One of the more positive symptoms of a full septic tank is an unusually lush lawn, confirming that every cloud really does have a silver lining. However, just because your garden is looking better than it ever has before, that doesn’t mean you don’t need to address the problem.
It’s a well-known fact that human waste acts as an excellent fertiliser. Urine, in particular, emerges from the body sterile and requires no treatment before boosting the growth of all kinds of flora in its vicinity. If your septic tank begins to overflow, these nutrients could creep into the nearby grass, making it greener than ever before.
While a flourishing lawn might just indicate that your horticultural skills are coming on in leaps and bounds, one which has been caused by a filled septic tank will usually be easy to detect. That’s because the area around the tank itself will have benefited from the fertiliser more than others, allowing you to catch the culprit green handed.
8) Algal blooms in nearby ponds
Another side-effect of overloading the surrounding area with too many nutrients from accidental fertilisation is the presence of algal blooms in ponds, lakes and other bodies of water. Having a pond on your property is an excellent way to increase the value of your home – but it can also serve as an effective barometer for whether or not wastewater from your septic tank has leached into the surrounding environment.
For those unfamiliar with what algal blooms actually are, they’re sudden proliferations of algae in the water. These are caused when the nutrient levels in the water become imbalanced, spurring rapid growth of the algae and covering the surface of the pond or lake. While that doesn’t sound too serious in itself, it’s actually a grave environmental concern.
That’s because the algae consume an excessive amount of oxygen in order to thrive, thus depriving other organisms within the ecosystem of a valuable resource they require to survive. What’s more, the layer of algal growth can also block out sunlight, thereby disadvantaging other species of plant living beneath them even further. If you spot an accumulation of algae in water near your home that wasn’t there before, your septic tank could be to blame.
9) High nitrate content in water wells
This red flag only applies to those who have a private well on their land from which they draw their water for drinking, irrigating their crops or plants and feeding their pets. While it’s the least common item on this list, it’s probably also the most serious and therefore more than merits its inclusion.
Anyone in charge for a private well that is designated for drinking water has the responsibility to check its quality on a regular basis. This ensures that those who imbibe it are doing so safely and healthily. If you discover that your drinking water contains higher than normal concentrations of nitrates, that could be an indicator that it has become compromised by run-off from your septic tank.
While nitrates are naturally occurring compounds, consuming an excessive amount of them is harmful to human health – especially for babies. As such, if you discover high nitrate levels in your well, you should refrain from using that water immediately and call in septic tank specialists to deal with the problem.
10) Backed up sewers
As well as being the most obvious sign that a septic tank is full, this is also undoubtedly the most disgusting. Other than the contaminated well outlined above – which will only apply to a small percentage of the population – backed up sewers are pretty much the worst-case scenario when it comes to a full septic tank.
That’s because no-one wants to have to witness sewage bubbling up from their sinks, toilets, showers or other drains in the home, let alone deal with the problem. If wastewater actively begins to back up out of the drains around your house, it will not only create an unsightly and unpleasant smelling mess, but it will also pose a health hazard. For that reason, anyone who discovers a backed-up drain should avoid the area until the appropriate professionals can arrive on the scene and handle it.
The good news is that this stomach-turning eventuality is invariably preceded by most of the other items on this list (but especially slow drainage and problematic flushing), so you should be able to spot the problem and address it long before things arrive at this crisis stage.
Why septic tank maintenance is so important
It should be apparent by now that neglecting to conduct regular maintenance on your septic tank can lead to a whole host of problems, each more unpleasant to deal with than the last. However, looking after your septic tank and ensuring it stays in good working order is not just good housekeeping – it’s also a legal requirement.
New laws came into effect in January 2020, which meant that all septic tanks which discharge their effluent into surface water drains (such as rivers, lakes or ditches) had to either upgrade into a full sewage treatment plant system or else relocate the discharge of the wastewater to a drainage field at a suitable distance from any existing water course.
Aside from these new restrictions, owners of a septic tank also have a legal responsibility to ensure that it is properly maintained. Overflowing septic tanks can cause damaging pollution, which upset the local ecosystems and jeopardise the survival of myriad types of flora and fauna.
Anyone found to be guilty of allowing contamination to occur on their premises could be subject to hefty fines. Depending upon the size of your property, the seriousness of the transgression and any past offences present on your record, that penalty could stretch into hundreds of thousands of pounds.
For those reasons, it’s imperative that you implement a strict maintenance schedule for your septic tank. As mentioned above, the frequency with which you should empty your tank and perform maintenance checks upon it will depend upon your unique circumstances, but a minimum annual inspection is advisable for all properties.
Those buying a new home or place of business with a septic tank attached should consult the previous owners, enquiring if they had such a schedule in place. This course of action will give you an idea of what to expect when putting in place your own maintenance regime. At the very least, you should ask them when the tank was last emptied, since this can give you an idea of when its next servicing date is due.
Call in the professionals
Do you have a septic tank on your property? Have you noticed any of the tell-tale signs outlined above? Even if you haven’t as yet, it’s a good idea to make sure your house is in order now to avoid any unpleasant eventualities further down the line. That’s why it makes sense to schedule a maintenance appointment with a qualified and certified septic tank specialist – such as ourselves.
At LetLoos, we have years of experiencing in addressing issues and offering tank emptying services for all kinds of models, from basic cesspits to standard septic tanks to Klargester systems. We deploy a skilled team of professionals and high-grade equipment to quickly, safely and hygienically remove all waste from your tank, before disposing of it in a legal and environmentally responsible manner.
We’re also equally at home when tackling small domestic jobs or large-scale commercial models, proving there is no project that’s too large or too small for our team. Regardless of the size or shape of your septic tank, we have the tools and the knowhow to offer reliable emptying services.
To find out more about the tank emptying services we offer, to arrange a consultation or to simply ask any questions about septic tank maintenance that might be troubling you, why not get in touch with LetLoos? Our friendly and professional team are always on hand to provide answers and insight, so you can rest assured that your septic tank is in good hands.