What to Do With an Abandoned Septic Tank: A Complete Guide

Old, unused septic tanks are more than just buried relics—they can be a safety hazard, an environmental concern, and a liability for homeowners. If you’ve recently moved into a property or discovered an old system on your land, you might be wondering, What should I do with an abandoned septic tank?

At No Worries Septic Services, we know how overwhelming this situation can feel. That’s why we’ve put together this complete, easy-to-follow guide to help you understand your options and take action safely, legally, and efficiently.

Why Abandoned Septic Tanks Are a Serious Concern

Before diving into the “what to do,” let’s take a quick look at why dealing with an abandoned septic tank is so important:

1. Health Hazards: Even if it hasn’t been used for years, an old septic tank can still contain toxic gases or contaminated sludge. If not handled properly, these materials can pose serious health risks to humans and animals.
2. Ground Collapse Risks: Over time, the walls of an unused septic tank can deteriorate. This creates a dangerous situation where the tank could collapse, potentially injuring anyone walking or working above it.
3. Legal and Real Estate Issues: In some areas, local or state codes require proper decommissioning of unused septic systems. Failing to address an abandoned tank can delay home sales, lead to fines, or create insurance complications.
4. Environmental Damage: A leaking, unsealed tank can contaminate groundwater and surrounding soil—harming nearby plants, animals, and potentially even your drinking water.

How to Identify an Abandoned Septic Tank

Sometimes, it’s obvious. Other times, it’s a mystery buried beneath your lawn. Here are a few signs to watch for:

• Old property records indicating septic use
• Sunken areas in your yard, especially in regular patterns
• Concrete or metal lids visible at or just below ground level
• Pipes or drainage lines leading to nowhere
• Previous owners’ remarks or disclosures about septic history

If you’re unsure, a professional inspection using cameras or probing tools can help locate the tank without damaging your yard.

What You Can Do With an Abandoned Septic Tank

So, you’ve confirmed the presence of an unused septic tank—what now? You have a few options, and each comes with its own considerations.

1. Have the Tank Properly Decommissioned: The most common and safest option is to decommission the tank. This involves:
2. Pumping out any remaining contents
3. Cleaning and disinfecting the inside of the tank
4. Filling it in with sand, gravel, or concrete
5. Removing or sealing access points to prevent collapse

This process ensures the tank can no longer pose any danger. In most areas, this must be done according to local codes and permits, which is why working with professionals like No Worries Septic Services is essential.

2. Remove the Tank Entirely: If you’re doing construction, landscaping, or building something new on top of the old system, complete tank removal may be necessary. This involves excavation and hauling away the tank (especially if it’s concrete or steel).

This can be more expensive than decommissioning, but it clears space and eliminates long-term liability.

3. Repurpose the Space (After Decommissioning): Once the tank has been safely cleaned and filled in, you can repurpose the area for:
4. A garden bed
5. A patio or deck
6. A shed foundation
7. Decorative landscaping or a tree planting zone (with caution)

Never build habitable structures over an old septic tank unless it’s been completely removed.

4. Do Nothing? Don’t Risk It: Leaving the tank untouched is a serious gamble. What might seem like a harmless patch of yard could become a sinkhole—or worse. Ignoring the issue can lead to major repair costs and put people or pets in danger.

Local Regulations You Need to Know

Each city and county has different rules when it comes to septic tank abandonment. In Washington State, proper decommissioning must be documented and sometimes inspected by local health departments.

It’s important to:

• Check with your local permitting office
• Work with a licensed septic professional
• Keep a record of the decommissioning or removal process

Why You Should Hire a Professional

Abandoned septic systems are not a DIY project. Here’s why:

1. Safety Risks: Opening or exploring a tank without the right equipment can expose you to toxic gases or physical injury.
2. Environmental Protection: A certified technician will ensure the tank is handled in a way that protects local water sources and soil.
3. Code Compliance: Professionals are up-to-date on the latest laws and know what documentation is needed for your property.
4. Peace of Mind: With the job done right, you won’t have to worry about future issues or liabilities.

Our Abandoned Tank Services at No Worries Septic Services

At No Worries Septic Services, we specialize in:

• Locating old tanks safely and efficiently
• Evaluating the condition of your system
• Pumping and cleaning abandoned tanks
• Properly decommissioning or removing tanks per state and local codes
• Providing documentation for future property records

We serve homeowners, realtors, contractors, and property managers in Pierce County, Thurston County, and King County and take pride in offering reliable, honest service.

Areas We Serve

At No Worries Septic Services, we’re proud to provide expert septic tank solutions across Western Washington. Whether you need to locate, decommission, or remove an abandoned septic tank, our licensed team is ready to help—promptly and professionally.

We serve homeowners, property managers, real estate agents, and contractors in the following counties:

• Pierce County
• Thurston County
• King County

No matter where you are in these regions, you can count on us for dependable service, expert advice, and total peace of mind.

Call (253) 271-6939 to schedule your service today or visit nwsepticservices.com to learn more.

Common Questions About Abandoned Septic Tanks

Q: Can I build over an abandoned septic tank?
A: Not unless it’s been removed or properly decommissioned. Always consult a professional before building over the site. Call (253) 271-6939 for more guidance.

Q: How much does it cost to remove or decommission a septic tank?
A: Costs vary based on size, location, and accessibility, but decommissioning is usually less expensive than full removal. Call us at (253) 271-6939 for a free estimate!

Q: Who is responsible for decommissioning an abandoned septic tank?

A: The property owner is usually responsible for properly decommissioning an abandoned septic tank. However, hiring a licensed septic professional ensures the process meets all local regulations and safety standards.

Need Help with an Abandoned Septic Tank? Call Us Today!

Don’t let an old septic tank become a future problem. At No Worries Septic Services, we make the process simple, safe, and fully compliant with all regulations.

Whether you need inspection, pumping, decommissioning, or removal—we’ve got your back. Let’s take this off your to-do list.

Call (253) 271-6939 to schedule your consultation or visit nwsepticservices.com for more information.No stress. No guesswork. Just No Worries!