How a soakaway works, and why it stops working
A traditional septic pit is not simply a sealed tank. Its walls and base allow the liquid fraction to seep gradually into the surrounding soil while solids settle at the bottom. That slow percolation through the pores is what lets a tank run for months before it needs emptying.
With use, a sticky biological layer of organic matter, grease and fine suspended solids forms on the internal walls. This layer progressively blinds the pores, so drainage capacity falls, and as it falls more liquid stays inside and the level rises faster.
The result the homeowner notices: a tank once pumped twice a year now needs monthly emptying, then weekly, with no change in occupancy or usage pattern. That acceleration is the clearest symptom of blinded pores.
What actually blinds the pores
| Cause | How it happens | Is restoration worthwhile? |
|---|---|---|
| Accumulated biological layer | Natural build-up over years | Usually yes |
| Fats and oils | Arrive from the kitchen and coat the walls in a sealing film | Yes, if the source is addressed |
| Non-degradable materials | Wipes and fabric mechanically blocking the pores | Yes, by cleaning |
| Harsh chemicals and detergents | Kill biological activity and alter soil properties | Partially |
| The surrounding soil itself clogged | Soil around the pit saturated with fine particles | Usually not |
| High groundwater table | Soil already saturated and cannot take more | No |
| Pit past its service life | Complete saturation of the soil around the excavation | No — needs a different solution |
Honesty requires saying it: the last three cannot be solved by opening the pores. In those cases restoration is money spent with no lasting result, and anyone promising otherwise is selling you a repeat visit rather than a solution.
Blinded pores or saturated soil? How we tell
This is the pivotal technical question, and the distinction determines whether treatment is worth doing at all:
Response test after emptying. Once the pit is fully pumped, we watch how fast the level rises. If it climbs noticeably despite normal domestic use, the surrounding soil is no longer accepting anything — a sign of saturation rather than blinded pores.
Wall inspection after emptying. Walls coated in a thick sticky layer mean blinded pores that can be treated. Relatively clean walls combined with rapid refilling mean the problem lies outside the pit, in the soil itself.
Site history. A pit many years old on a site whose use has not changed, with a gradual acceleration over months, has usually reached the end of its service life. Sudden acceleration over a few weeks points instead to an acute cause, such as water leaking into it or material that blinded the pores all at once.
Unexpected water sources. We check there is no leak from a tank or supply line discharging into it, and that rainwater is not entering. Sometimes “the tank fills too fast” is a clean-water leak rather than a septic problem at all, which water leak detection uncovers.
Work it out yourself: when restoration is the economical call
Rather than debating it in the abstract, a simple calculation settles the decision. Look back at your pumping invoices for the past six months and work out:
How many times was the tank emptied? What was the interval between visits? And what was that interval a year or two ago? If the interval has halved or worse, you are paying twice what you were for exactly the same service — and that increase is still climbing, not level.
Restoration becomes a clear economical decision when its cost is less than the expected extra pumping cost over the next six to twelve months. Because the outcome cannot be guaranteed in every case, we prefer to start with diagnosis: a full pump-out and wall inspection costs you what you would have paid for pumping anyway, and in return gives you a clear answer on whether restoration is worth committing to.
And if the diagnosis shows the soil is saturated, you have saved yourself the cost of a treatment that was never going to work, and moved straight to discussing real solutions. Either way, diagnosis first is the cheaper decision.
What we actually carry out
1. Full pump-out and condition assessment
We empty the pit completely, because any assessment made over standing liquid is meaningless. We then inspect the walls and base and establish the thickness and nature of the accumulated layer.
2. Pressure washing the walls
We wash the internal walls with high-pressure water to strip the biological and greasy layer blinding the pores. This is the substantive step in “opening the pores”; promises that skip it have no basis.
3. Removing hardened base deposits
The hardened layer in the base prevents downward drainage and reduces effective capacity. Removing it restores part of the lost volume.
4. Checking the inlet line and base
We confirm the problem is not in the line feeding the pit in the first place, because a blocked inlet is sometimes misdiagnosed as a full tank.
5. Drainage test and a clear decision
After cleaning we observe how the pit behaves. If drainage improves, the treatment worked and we recommend a preventive schedule. If it does not improve despite clean walls, we tell you plainly that the problem is in the soil and that treatment will not help, and we discuss other options instead of repeating pointless visits.
Why we are cautious about advertised chemicals
Products sold as opening soakaway pores “instantly” are widely marketed, and our position on them is straightforward:
Strong acids may produce a temporary surface effect, but they damage the concrete of the pit walls and the connected pipework, can be hazardous to handle, and their effect on the surrounding soil is undesirable. Harsh detergents kill the biological activity that helps break down organic matter in the first place, making things worse over the medium term.
Biological (bacterial) products are far less harmful and may help reduce organic build-up with regular use, but they are not a solution for pores blinded by a thick layer accumulated over years, and they achieve nothing at all where the soil is saturated.
Our practical position: mechanical removal by pressure washing is what produces an observable result, and any product offered as a substitute for actual cleaning should be treated with caution.
When restoration will not work, and what then
We reach that conclusion in clear circumstances: rapid refilling despite clean walls after washing, evident saturation in the surrounding soil, or a pit years beyond its service life.
In those cases we set out the options honestly: reviewing whether the property can be connected to the public sewer if it is available in the district — the definitive solution that ends the pumping question for good; studying a suitable alternative arrangement for the site; or, as an interim measure, setting a regular septic pumping schedule at a known cost rather than scattered emergency call-outs.
What we do not recommend is continuing to pay for repeated “pore opening” on a pit that has genuinely reached the end of its capacity. Repeating that treatment over a year can exceed the cost of the definitive solution itself.
Extending the life of the pit after treatment
- Keep fats out of it: oils are the primary enemy of the pores because they form a sealing film. Never pour oil into the sink, and fit a strainer on the kitchen sink.
- Do not flush wet wipes: they do not break down and remain to block the pores mechanically.
- Reduce harsh detergents and bleach: excessive use suppresses the biological activity inside the pit.
- Keep rainwater out entirely: stormwater entering consumes capacity for no reason and accelerates filling during the season.
- Fix any supply-side leak: a continuous leak from a tank or pipe means clean water filling the pit to no purpose.
- Keep to a regular pumping schedule: letting the pit fill to the very top drives solids against the walls and accelerates pore blinding.
- Consider a planned maintenance schedule if the site is commercial or heavily used.
Soakaway and septic questions
What does opening the soakaway pores mean?
It means removing the biological and greasy layer accumulated on the walls and base of the pit — the layer that blinds the pores and stops liquid percolating into the surrounding soil. It is done by high-pressure washing after a full pump-out, not with chemicals.
Why does my tank fill faster than it used to?
If occupancy and usage have not changed, the cause is usually blinded pores, saturated surrounding soil, or extra unaccounted water entering such as a supply leak or rainwater. Telling them apart is done by inspecting the walls after pumping and watching how fast the level rises.
Do chemical products really open the pores?
Strong acids may give a temporary surface effect but damage the pit concrete and connected pipework and can be hazardous. Biological products are far less harmful and may reduce build-up with regular use, but they cannot clear a thick layer accumulated over years and achieve nothing where the soil is saturated.
How do I know the problem is the soil rather than the pores?
The clearest indicator is the level rising quickly after a full pump-out despite normal domestic use and relatively clean walls. At that point the surrounding soil has reached saturation, and treatment inside the pit will change nothing because the problem is outside it.
How long does the result of pore restoration last?
It varies considerably with soil condition and usage pattern. The result lasts longest where the cause was an accumulated layer on sound walls and the surrounding soil can still accept liquid, and is much shorter where there is partial saturation. That is why we do not give a time promise before seeing how the pit behaves after cleaning.
What is the alternative if the pit has reached the end of its life?
The definitive solution is reviewing whether the property can be connected to the public sewer if available in the district, because it ends the pumping question for good. As an interim step, a regular pumping schedule at a known cost is more economical than repeating treatments that produce no lasting result.
Related septic services:
If the tank is full right now, start with septic tank pumping, and for problems with the pit structure itself see septic tank drain cleaning. If rapid filling comes with damp in the yard, the cause may be a leak found by leak detection.