Septic Tanks Are Hawaii’s New Wastewater Cleanser

53 million gallons of untreated sewage was released into the ground every day in Hawaii in 2017 – (page 3)

Since then, Hawaii has passed Act 125 to clean up this problem. In short, it means cesspools are to be replaced by septic systems or connected to a sewer by 2050.

One of the best alternatives is a septic tank. This guide to septic tanks can give you answers to these questions:

  • What is a septic tank & how does it work?
  • Are there different types?
  • What are the differences between septic tanks and cesspools?
  • What are the costs?
  • How do you clean and maintain septic tanks?
  • What are some common possible problems?
  • What are Hawaii’s septic tank regulations?

Let’s dive into the septic tank regulations for Hawai’i.

Septic Tank Installation Kona

What Is A Septic Tank & How Does It Work?

Septic tanks are basically like Brita filters in that they help cleanse water. They are usually made from concrete or fiberglass.

Septic tanks are normally made of 3 parts:

  • A tank that stores, separates, and starts treating waste
  • A distribution system that distributes the cleaner wastewater into the surrounding soil
  • The soil in the absorption field around it that finishes treating the wastewater

These parts all work together to help keep your environment, and your water, clean. It does this by separating the solid and floatable waste from the water:

  1. Wastewater flows into the septic tank
  2. Over time lighter waste floats and heavier waste sinks
  3. Bacteria in the tank break it down into nutrients, gas, and water
  4. The wastewater flows out of the tank via the distribution system
  5. Surrounding soil (drainage field) removes contaminants
  6. The solids are pumped out by a professional

The best type of soils are well-drained, medium textured soils like loam.

Let’s see how cesspools compare to septic tanks when it comes to saving the earth.

Schematic of septic tank system
Diagram by wfeidenlicense

Types Of Septic Tanks

First, we have aerobic vs anaerobic septic tank systems. What it comes down to is whether the bacteria treating your waste uses oxygen or not.

Aerobic bacteria septic systems are better than anaerobic systems at:

  • Breaking down human waste
  • Treating wastewater
  • Not taking up space
  • Giving failure alerts
  • Can be used anywhere
    • Anaerobic systems are required close to the shoreline and high groundwater areas

But, aerobic systems also require more maintenance, more money, they clog, more easily, and they can break down more.

Now we get into the actual materials it can be made from. For systems manufactured in Hawai’i, you can choose between:

  1. The OESIS-750 SYSTEM
  2. The CBT 0.8KF-210 SYSTEM

You can learn the specifics about these systems on page 5-32 & 33 >>

Septic Tanks vs. Cesspools

There is a reason why cesspool is also defined as “a disgusting place”. Cesspools are underground storage for liquid waste and sewage.

It’s basically a manmade hole in the ground that lets wastes seep out of it.

Unlike cesspools, septic tanks:

  • Remove solids from wastewater
  • Use bacteria to start treating the water
  • Help break down contaminates
  • Release water higher up for better decontamination
  • Are better overall for the environment

We know it can be a pain to install a new wastewater treatment system. But, you’ll be helping to keep the water clean for yourself and your family.

Speaking of pains, let’s take a look at the costs that come with septic tanks.

Cesspool diagram
Diagram by Destination Maui

Costs Of Septic Tanks

Septic tank installation here on the big island starts at about $10k and averages $14k-$15k.

Of course, an average varies greatly depending on where, type, installer, and other factors.

As for the cost of the tank itself:

  • 1,000-gallon tank for 3 bedroom house: ~$2000
  • 1,200-gallon tank for 5-6 bedroom house: ~$2500

Thankfully, the cost of pumping out a septic tank isn’t as much as installing one. Pumping prices can vary depending on the size and severity, but it can range from $300-$500.

Cleaning & Maintenance Of Septic Tanks

Cleaning and maintenance are all about pumping out the sludge regularly and on time.

Maintenance involves pumping out your septic tank every 2-3 years. The cost for this service can range from $300-$400. If you keep it working well then you should experience little to no problems.

As for cleaning your septic tank, you can do it yourself, with a garden hose! The effluent filter must be cleaned every 1-3 years

Septic Tank Installation Kona

3 Common Problems Possible With Septic Tanks


These are a big problem with septic tanks. Waste will pile up and eventually there will be no more room in the tank left. This can result in backups into the house and slow draining.

Solve this problem by having a professional clean your tank.

Tree Roots

These bad boys can wrap around and drill straight through almost anything in their way. This can make them work slowly or not at all.

Solve this problem by removing trees or installing in areas without roots.

Broken Drain Lines Or Baffle

The waste can go any and everywhere if these break down.

Solve this problem by having the broken part replaced.

Hawaii’s Septic Tank Regulations

Hawaii’s list of regulations for septic tanks involves:

  • Concrete or fiberglass material
  • Preferred types like:
    • The OESIS-750 SYSTEM
    • The CBT 0.8KF-210 SYSTEM
  • Meeting International Association of Plumbing and Mechanical Officials standards
  • Approval and installation by a licensed septic engineer and permitted through the Department of Health
  • Waste being discharged into a soil absorption system, a sand filter, a subsurface irrigation system (with director approval), or
    another treatment system
  • Installation of a screen on the effluent end of the septic tank

You can read more details and regulations >>

Provide Cleaner Water With A Better System

You can reduce water and environmental pollution by using septic tanks. It may cost a little more, but at least you won’t have to worry about getting diseases from swimming or drinking water.