Septic Tank Installation: How to Do It Right

Septic tank installation isn’t rocket science, but mess it up and you’ll have a stinky, expensive disaster. After helping with dozens of installs, I’ve learned what works and what causes problems.

Get Your Paperwork First

Call your county health office before you buy anything. Trust me on this. They’ll tell you what permits you need and what rules to follow. Some counties make you test the soil before they approve anything.

I skipped this step once and regretted it when the inspector showed up and made me move everything. Learn from my mistake – get permits first.

Pick the Right Spot

Your septic tank needs to go in the right place. Keep it away from wells and streams. Most counties want it at least 50 feet from water sources and 10 feet from your house.

Look for high ground that drains well. Avoid spots where water pools after rain. And think about how the pump truck will reach it later – they need to get within about 50 feet.

Choose The Right Tank For Your Septic Tank Installation

You’ve got three main choices for tanks:

• Concrete tanks: Last forever but weigh tons. You’ll need heavy equipment to set them in place.
• Fiberglass tanks: Weigh less and won’t rust or crack. They cost more upfront but often last longer.
• Plastic tanks: Are cheapest and lightest. Easy to install but can shift in wet soil. Not great in areas with high water tables.

I’ve installed all three types. For my money, fiberglass offers the best middle ground.

Dig the Hole

Now for the hard work. Mark your tank spot based on the size of your tank. Dig about a foot wider than the tank on all sides. Depth depends on your local frost line and tank height.

The hole needs a flat, level bottom. Add a few inches of gravel to create a stable base for the tank.

Most DIYers rent a backhoe for this job. Hand digging works for small tanks, but you’ll hate life if you try it with anything bigger than 500 gallons.

Set the Tank

Lower the tank into the hole carefully. Make sure it sits level – check with a long level on the top. Even a slight tilt causes problems later.

Connect the pipe from your house to the inlet side of the tank. The pipe needs a gentle downhill slope – about 1/4 inch drop per foot of pipe.

Build the Drain Field

Dig trenches for your drain field pipes. How many depends on your soil and house size. Usually 3-4 trenches about 30 feet long works for a 3-bedroom house.

Put 6 inches of gravel in each trench bottom. Lay perforated pipes on top with the holes facing DOWN (a common mistake is putting them facing up). Cover the pipes with more gravel until you have 2 inches over them. Then, lay filter fabric over the gravel to keep dirt out.

Cover Everything Up

Backfill around the tank carefully. Add soil in layers and tamp it down gently. Don’t use heavy equipment right over the tank – you might crack it.

Fill the trenches with soil too, making a slight mound to allow for settling. Plant grass seed right away to prevent erosion.

Test Before You Trust Your Septic Tank Installation

Before you flush, fill the tank with water. This tests for leaks and helps the tank settle.

Run water from your house to make sure it flows right. Check all connections for leaks. It’s better to find problems now than later when the bathroom backs up.

Septic Tank Installation Horror Stories

Jake from down the road thought burying his tank extra deep was smart. “No freezing pipes for me!” Yeah, right. Six months later the pump truck shows up—their hose reaches 12 feet. His tank? Buried 14 feet down. What a nightmare. The guy spent a week digging up his yard by hand and ended up needing three extension risers just to reach it.

My uncle Tom did the same thing back in ’08— not quite as deep, but still a mess. The pumper charged him double because of the extra work.

That couple near the lake who tried saving on gravel? Big mistake. “We’ll just use half what the manual says,” they figured. Their system completely failed after just two years—ending up costing over twenty grand for fixes that a few extra hundred dollars of gravel might have prevented.

Speaking of dumb moves—a farmer once drove his tractor right across his new drain field. In his hurry planting corn, he crushed every pipe and compressed all that loose soil into concrete. Complete system failure.

And then there was the neighbor who thought county regulations were “just suggestions.” He put his tank barely ten feet from his well because it was easier, saying, “It’s my property!” But the health department disagreed—making him dig everything up and move it at a huge cost (plus a fine).

Keeping Your System Running Right

After your septic tank installation, your job isn’t done. Feed your system right and it’ll last decades.

Schedule pumping before problems start. For most families, that’s every 3-5 years. My neighbor once waited 12 years—resulting in his Christmas dinner being interrupted by sewage backing up into his bathtub.

Trees and septic systems don’t mix. Those roots sense water and head straight for your pipes. Keep trees at least 30 feet away from your drain field.

Never drive on your system—no cars, ATVs, or heavy mowers. I mark my drain field with small garden stones to remind everyone.

Watch what goes down your drains too. Wipes clog pipes no matter what the package claims, grease forms nasty blobs, and harsh chemicals kill the good bacteria your tank needs.

Septic Tank Installation: Is It Worth Doing It Yourself?

Most folks who install their own septic tanks save thousands. Materials for a basic system run about $3,000–$5,000, while professional installation often costs $10,000–$15,000 for the same job.

But mess it up, and you’ll spend twice that fixing problems. If you’re not sure about any step, get help. Some folks DIY the digging but hire pros for the critical connections.

Either way, a properly installed septic system should last 25–30 years with basic care. It’s worth doing it right the first time.