Oscar Castillo
"Residential" Real Estate

Septic Tank System Layout and flow

As-you-know, the homeowner/s are responsible for maintaining their septic tank system. Consistent care and attention of your system are essential to preventing a septic system failure.

As a Realtor, I am so surprised to hear from people who have septic systems yet they do not know where their septic tank is nor where their leach-line drainfields are located in their property. My immediate thought is…WOW these homeowners have not done anything to maintain their system for quite some time – Yikes !!! (this not bueno ! )

For your bank account sake, health sake and to avoid any embarrassment due to a possible system failure when visitors or family members come over, you are urged to stop ignoring your septic tank system or it could become very $$ expensive to repair once the system fails.

It is recommended that the homeowner contact a qualified licensed septic system service company to periodically send a technician out to inspect and care for your septic system.

The frequency with which you need to schedule an inspection and a septic-tank-pumping depends on the size of the tank, the family size, and whether you use a garbage disposal unit or not. The system, ideally should be inspected about once each year. Generally, septic tanks should be pumped-out every 3 to 5 years or when needed. You really do not want to wait until you have a problem.

How septic systems work – in General

The septic system is a natural method of treating and disposing liquid household waste. The first component of all septic systems is the tank. Most tanks, built after 1996, are “split” into two compartments (aka: Split Tanks, Dual or Two Chamber Tanks) and have pipe baffles (directs flow of fluids) and an outlet filter to ensure the solids stay in the tank.

The biological process begins in the tank where the effluent (untreated waste) separates into layers and begins the process of decomposition. Bacteria, which are naturally present in all septic systems, begins to digest the solids that have settled to the bottom of the tank, thus transforming a large percentage of these solids into liquids and gases.

When liquids within the tank rise to the level of the “outflow” pipe and actually starts to flow out of the septic tank, then from this point the liquids go into the next stage of the septic treatment system. Liquids will then flow to the optional “distribution box or pump chamber” – this depending on your type of system.

The “final” treatment of the system effluents will be the transfer into the soil where additional microbes break down the liquid waste and the salvageable “clean” water, if any, is absorbed back into the ground.

Most all homes have one of 2-Systems in place (1) Standard Gravity and (2) Pressure Distribution

(1Standard Gravity - System

As the name implies, gravity drainfields work by letting gravity drain the effluent from the septic tank into a series of underground pipes (known as: Leach Fields and/or Leach Drains). This means the drainfield area must be below the elevation of the septic tank. If this is not the case, then a pump is necessary and it is called a pump to standard gravity system.

(2Pressure Distribution - System

Pressure distribution systems are usually required when there is less than optimal soil depth available for complete the “final” treatment of the effluents by the ground gravity system. A minimum of 2-feet of ground depth is required under the trenches for the leach line and drainfields. When the nearby soil will not allow the minimum of 2-feet to be dug up, then a “pump and/or a distribution box” is used to pressurize the effluents through an underground PVC pipe which will literally transport it to another area where the drainfield can meet the "depth" minimum requirements for optimal treatment into the soil.

How do you know if your system is failing?

 Toilets are slow to flush.

 Water backs up into sinks, toilets, bathtubs, and laundry machines.

 Gurgling sounds are heard when running water or flushing toilets.

 Grass is a deeper green color over the septic system area.

 Patches of unusual puddles and sogginess.

 Depressions forming in the soil (by or at the leach-line drainfields)

 Unpleasant smell in or around the house.

Flush toilets responsibly !

Toilets and your septic system are not trash cans! DO NOT flush products that do not easily degrade (ie: non-biodegradable). Keeping it simple. An easy rule of thumb is… do not flush anything besides human waste and toilet paper...Never flush:

 Cooking oils

 Grease or fats

 Flushable wipes

 Feminine hygiene products

 Facial Tissue


 Dental floss

 Disposable Diapers (or cloth types)

 Drain cleaners

 Cigarette butts

 Coffee grounds

 Cat litter

 Paper towels

 Cotton Swabs

 Pharmaceuticals (medications)



 Any household chemicals like gasoline, motor oil, pesticides, antifreeze, and paint or paint thinners.

What if my home has a Garbage Disposal?

Some experts say that if you have a septic tank system, you should get rid of the garbage disposal or at-least greatly limit the use of it. This will significantly reduce the amount of fats, grease, and solids that enter your septic tank and ultimately will clog its drainfield.

If you consistently use a garbage disposal, seriously consider an upgrade to a larger septic tank and have it pumped-out more often.

The following tank size guide pertains only to septic tanks of Residential Homes.    

 1,200 gallons                for 1 to 3 bedroom house

 1,500 – 1,650 gallons   for 4 bedroom house

 2,000 gallons                for 5 bedroom house

 2,500 gallons                for 6 bedroom house

Maintain Your Drainfield

Your drainfield is the final component of your septic system that removes contaminants from the effluent liquid that emerges from your septic tank. Here are a few things you should do to maintain it:

Plant only grass over and near your septic system. Plant trees and shrubs at the appropriate distance from your drainfield. Tree and shrub roots can interfere and damage the system. A septic service professional can advise you on the proper distance - this depending on your septic tank system and landscape.

 Never park a vehicle or drive on your drainfield

 Keep livestock, and other heavy equipment off the septic system area.

 Avoid building structures or driveways over the leach fields or anything such as extended patios that limit access to the septic leach lines, the "tank" and/or the distribution box.

 Use Water Efficiently

Did you know that the average indoor water use in a typical family home is nearly 70 gallons per individual per/day?  A “leaky or running” toilet can waste as much as 200 gallons of water per day.

All of the water that a household sends down its pipes ends up in its septic tank system.

The more water a household conserves, the less water goes into the system therefore this helps to eliminate any unnecessary strain. Remember that efficient-water-use is the conservation of water, thus the practice of less water usage greatly helps the operation of a septic system and helps reduce the risk of failure.

Hopefully you will find this information helpful.

If you have any issues with your system, make sure you contact a local licensed/certified Septic System service professional-technician and have them come out and inspect your system.

Oscar Castillo


(858) 775-1057

DRE# 01140298





Search The MLS Get Green Market Value

Posted By Oscar Castillo on Fri, Nov 11th 2022 5:45 pm
Inflation not a friend to current home Buyers and Sellers

I do not know of one person who has not been affected by this current "inflation" nightmare that we are all living in.  As-you-know inflation has "rocked" everyone's world in the sense that the...Read More

Posted By Oscar Castillo on Fri, May 13th 2022 1:15 pm
Mortgage interest rates trending upward - Lock in the Lower best rate

Interest rates have been going up-and-up and will continue to rise again and again. Unless you have had your head "in the sand" and/or are not keeping up with the latest Real Estate/Business News...Read More

Home Sales Realty Listingbook

Blog Categories