Drain Field Repair & Replacement in Nanaimo

What your drain field does

Your septic tank separates solids from liquid. The drain field, also called a disposal field or leach field, does the rest. Liquid from the tank flows into pipes buried in gravel or sand, then soaks into the soil, where it's naturally treated.

When the field works, you never think about it. When it stops working, the liquid has nowhere to go. It backs up into the house or surfaces in the yard.

Signs of a failing drain field

• Soggy ground or standing water over the field, especially when it hasn't rained
• Sewage smells in the yard
• Extra-lush, green grass over the field lines
• Slow drains or backups that come back soon after pumping
• Gurgling in plumbing
• High-water alarms on pump systems
• Sewage surfacing in the yard

If you see sewage on the surface, keep kids and pets away and call our local line.

Why drain fields fail

1. Solids escaping the tank. Skipped pump-outs or broken baffles let sludge flow into the field, where it clogs the soil. This is the most common cause, and the most preventable.
2. Too much water. Leaky toilets, many loads of laundry in one day, or a home with more people than the system was designed for can flood a field.
3. Compaction. Driving or parking on the field crushes pipes and compacts soil.
4. Roots. Trees and shrubs planted too close can grow into pipes.
5. Age. Fields don't last forever. Soil gradually loses its ability to absorb.
6. Wet weather and high water tables. Heavy rain can saturate soil. Struggling fields often show it first in the wet season.
7. Grease and chemicals. Fats and harsh products can damage the soil's ability to treat wastewater.

Repair or replace?

Not every struggling field needs replacing. Depending on the cause, options may include:

• Fixing the cause upstream: repairing baffles, adding an effluent filter, fixing leaks, pumping the tank
• Clearing or repairing lines that are blocked or broken
• Fixing or levelling the distribution box so effluent spreads evenly
• Resting the field, where the design allows it
• Reducing water use while the field recovers

If the soil itself has failed, replacement is usually the answer. That means a new design based on your soil and site, followed by installation.

A registered septic pro will diagnose the cause first. Be cautious of anyone who recommends full replacement without explaining why.

Drain field replacement in BC

Replacement is a significant job. Under BC's Sewerage System Regulation:

• The new system has to be designed and installed by an authorized person: a Registered Onsite Wastewater Practitioner (ROWP) or a professional engineer.
• The work has to be filed with the regional health authority, Island Health here, before construction.
• The authorized person provides a maintenance plan when the work is complete.

Your septic pro handles the design and filing. Ask what's included in the quote.

Save with the RDN SepticSmart rebate

The Regional District of Nanaimo's SepticSmart rebate has offered $700 toward the repair or replacement of an aging system for work valued over $10,000 on qualifying RDN properties, done by an authorized person. Pre-approval is required before work starts. Check the RDN's current rules before booking.

Protect your drain field

• Pump your tank on schedule, usually every 2 to 5 years per HealthLinkBC
• Keep vehicles, trailers and livestock off the field
• Plant only grass over the field. Keep trees and big shrubs well back.
• Direct roof drains and runoff away from the field
• Spread out laundry and fix leaks
• Keep grease, wipes and chemicals out of your drains

Drain field FAQ

How long does a drain field last? It varies widely with soil, design, use and maintenance. A well-maintained field can last for decades. A neglected one can fail much sooner.

Can a drain field recover? Sometimes, if the cause is fixed early and the field gets a chance to rest. A field that's been clogged with solids for years usually can't.

Can I put a shed or patio over my drain field? No. Keep structures, paving and vehicles off the field. The soil needs air and the pipes need protection.

How long does replacement take? Design and filing come first, then installation. Your provider can give you a timeline once they've seen the site.

What affects the cost of drain field work

Drain field work ranges from minor fixes to full replacement, so costs vary widely:

• Repair vs. replacement. Clearing a line or levelling a distribution box costs far less than a new field.
• Soil and site conditions. Rocky ground, shallow soil, slopes and high water tables can require specialized designs, which often cost more.
• System type. Some sites need pumps, pressurized distribution or treatment units.
• Size of the home. Fields are sized to expected wastewater flow, which depends on the home.
• Access and restoration. Excavation equipment needs room, and lawns, fences and driveways may need repair afterwards.
• Design and filing. Replacement requires design and filing by an authorized person.

Get a written quote that includes design, filing, installation, materials and site restoration.

Questions to ask before you approve a replacement

1. What exactly failed, and how do you know?
2. Could a repair, resting the field or fixing the cause upstream work instead?
3. What type of system will replace it, and why that type?
4. What's included: design, filing with Island Health, installation, restoration?
5. How long will the job take, and can we use the house during it?
6. What maintenance will the new system need?
7. Is there a warranty?

A trustworthy provider will answer every one of these clearly.

Get your drain field assessed

Call our local line or send the quick quote form. Tell us what you're seeing, and a registered local septic pro will get back to you to assess the field and quote the fix.