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What goes into calculating drain field size?
A properly sized drain field is essential for an efficient and long-lasting septic system. If a drain field is too small, it can lead to system overload and failure. If it’s too large, you may be spending more than necessary on installation. So, how do professionals determine the right drain field size for your property?
Key Factors That Determine Drain Field Size
1. Household Size & Water Usage
- The number of people in your home directly affects how much wastewater your system needs to process.
- More bathrooms, laundry loads, and appliances mean a larger drain field is needed.
2. Soil Type & Absorption Rate
- Different soils absorb water at different rates.
- Sandy soil drains quickly and may need a smaller field.
- Clay or dense soil drains slowly, requiring a larger drain field.
- A percolation test (or "perc test") is conducted to measure how fast water is absorbed.
3. Septic Tank Size
- The drain field must be proportional to the septic tank.
- A common rule is that a 1,000-gallon tank pairs with about 400-600 square feet of drain field.
- Larger tanks require larger fields.
4. Local Regulations & Codes
- County and state health departments have specific guidelines on drain field size.
- These regulations help prevent contamination and ensure proper wastewater treatment.
5. Property Layout & Space Availability
- Your lot size and landscaping impact drain field placement.
- Drain fields must be set back from wells, structures, and property lines.
Why Proper Drain Field Sizing Matters
✔ Prevents system overload and backups
✔ Extends the life of your septic system
✔ Reduces the risk of groundwater contamination
✔ Ensures compliance with health regulations
If you're planning a new drain field installation, Atlantic Septic can assess your property, conduct a percolation test, and design the perfect system for your needs. Contact us today for a consultation!