Septic perc + sizing calculator (AZ ADEQ Type 4)
How big a septic tank and leach field do you need to pass an Arizona ADEQ Type 4 permit? Tell us your bedroom count and your perc rate — we'll size both.
Result
- Daily flow
- Septic tank
- Leach field
- Soil class (AZ ADEQ)
The two outputs. Tank size is fixed by AZ ADEQ Table 4 from your bedroom count (1,000g for 1-3BR, 1,250g for 4BR, 1,500g for 5BR). Leach field area scales with your perc rate — slow soil needs more area to absorb the same daily flow.
Cost reality. A standard ADEQ Type 4 install runs $8K-$20K depending on excavation difficulty (caliche layers add cost). If your perc rate is >120 min/inch you'll need an alternative system (mound, sand filter, ATU) which can run $25K+. Get a second perc test before committing.
Recommended gear
Affiliate links — Plotnode may earn a commission from purchases at no extra cost to you.
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AmazonAero-Stream septic tank riser kit23.5" diameter × 10" tall. Brings access lid to grade so you can pump without digging.
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AmazonRid-X septic tank treatmentMonthly bacterial enzyme dose. Keeps the tank biology healthy between pump-outs.
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AmazonLAND 100ft open-reel fiberglass tapeHeavy-duty for laying out perc test grids and leach field footprints.
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