Ample Tank and Component Access Is a Maintenance Must

Entry points from a clean-out at the outside wall of the house to an inspection port at the end of the drainfield make troubleshooting a breeze

Ample Tank and Component Access Is a Maintenance Must

For safety, follow the manufacturer’s recommendations for properly securing access lids brought to the surface.

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Over the years, I have seen a lot of access problems associated with sewage tanks, including septic, pump and aerobic tanks. As a part of any management program, regular maintenance of tanks must be performed. Some regulatory agencies require either periodic inspection or regular solids removal. Cleaning a septic tank properly requires access through a manhole or manholes that allow access to all corners or compartments of the tank.

This requires an opening at least 20 inches in diameter, allowing cleaning and inspection of the tank as a part of regular maintenance, as well as access to inspect tank baffles. In most areas, an effluent screen is required at the outlet baffle of the septic tank. I have been with service providers more than once when the outlet baffle and effluent screen were under the lid, so the only way to clean the screen is to remove the lid. Working with the tank manufacturers to make sure the tanks have access to the baffles is important.

Providing proper access means the service provider will not have to hunt for an hour to find the tank and access points. This means bringing access points to the surface using risers and lids. Remember, though, that while the goal is to provide access to service providers, it is important that the lids be secure and prevent entry by unauthorized people such as children and homeowners. Every year you read in the news about a child who accidently fell into a septic tank and was seriously injured or even died.

Securing lids if they are plastic products means that all the lid screws are in place, including the one “safety screw that is different from the others.” The weight of concrete lids is somewhat of a deterrent but not enough; they should be chained and locked to prevent entry. It is also good to have an additional safety device or net inside the risers above the tank. Numerous products on the market will keep people or items from falling into the tank itself.

Similar situations to the effluent screen occur in pump tanks. To service or replace a pump or control floats in a system, they must be accessible. It’s important to use a pump tree for the pump and floats with a chain or rope attached so they can be removed from the tank for maintenance. This also means that the piping has quick-disconnect connections so the service provider does not need to cut the supply pipe to remove the pump.

Expand your access 

Just like the tank and effluent filters, you want to plan ahead to provide easy access to all system components. If there is a problem or blockage in one part of the system, you want service providers to be able to identify and correct the issue without impacting or disturbing other parts of the system.

I remember a workshop that some colleagues and I conducted where we visited a residence and saw that wastewater was standing in the sewer pipe running from the house to the septic tank. The homeowners informed us that they had continual problems with backups in the sewer line. This was no surprise because the sewer pipe either was not laid on the proper grade or it was deflected during backfill. As a result, the pipe did not run empty between water-use events in the house. This allowed solids to accumulate in the pipe, resulting in blockages.

Properly laying and backfilling all piping is important to good system installation. An ASTM standard (2321) covers properly embedding and backfilling piping installed in trenches. The pipe should be surrounded and stable so that it stays on proper grade and does not develop dips that may collect solids and lead to blockages. I would add this also prevents water from collecting and freezing, causing blockages in cold climates.

Properly installed pipe must be on a compacted aggregate base or suitable natural soil, then the initial backfill, or haunching as it is called, is placed halfway up the pipe before final backfill around and above the pipe. Backfill should be clean, unfrozen material. This means no rocks that can deflect the pipe or crack or break it. Final backfill should be crowned to allow for minor settling and to shed surface water. Final backfill should be suitable for establishing vegetation to prevent erosion and help with frost protection in cold climates.

In terms of access to the sewer line, a clean-out should be installed outside the residence. This should be a two-directional clean-out so it can be cleaned going both toward the residence and toward the septic tank.

Having the clean-out outside means blockages — should they occur — can be removed without having access to the residence. This allows the service provider to work without having someone home to provide access and avoids the common issue around finished basements where the inside clean-out has become hidden by Sheetrock walls.

Inspection ports

A key component of system management is to provide the ability to assess whether the soil treatment area or drainfield is accepting the effluent delivered. Again, many regulatory management programs require providing inspection ports in drainfield trenches or beds.

From a system management standpoint, this allows a quick way to see whether effluent is ponded in the system and what proportion of the system is being used. A number of years back, I remember recommending inspection ports in trenches. Some of the first installations resulted in what I would term “unsecured” inspection ports. They were easily extracted from the trench the first time the push-on cap was removed, rendering them useless.

The following are some guidelines for locating and securing inspection ports. They can be installed at both ends of the trench or bed. The pipe should extend to the bottom of the trench or bed. Holes should be drilled in the pipe up to the level of the top of the trench or bed. The pipe should extend from the top of the system to the ground surface or above. It should not be connected to distribution piping.

Many homeowners object to a bunch of pipes sticking above ground, and they also seem to draw riding lawn mowers like magnets. An effective way to provide access is to bring them into a valve box at the surface. That way they are easily found and identifiable. Caps on the pipe should be screw type. If slip or push-on caps are used, they should be slit on the side to allow easy removal.

There are three primary ways the inspection ports can be secured in rock systems. They can be anchored using a 12- to 18-inch section of rebar, a pipe tee created at the bottom of the pipe, or using and anchoring a toilet flange at the bottom of the pipe. The goal is to securely anchor the inspection port so it does not move around or get accidently removed when accessed. It also ensures a consistent measurement of liquid depth.

For chamber systems, the pipe is attached to the chamber at the port location provided with stainless steel screws. In the chamber, the pipe extends to the infiltrative surface and is perforated to allow an accurate measure of liquid depth. For any proprietary products, remember to follow the manufacturer’s instructions. 


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