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Permeable Interlocking Concrete Pavement (PICP) Infiltration Storage Calculator

Calculate the stormwater storage volume provided by a permeable pavement's aggregate reservoir layer.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Stormwater storage volume

3170.06 gal

Check your inputs

Void ratio depends on the specific aggregate gradation used — confirm the actual void ratio for your chosen open-graded base material (commonly tested per ASTM C29) rather than assuming a generic value.

Running these inputs gives 12000 as the stormwater storage volume. Note that permeable pavement surface area sits at the low end of the range this calculator was checked against, so treat the output as indicative rather than settled. Expect some drift against the real job; the calculation is solid but conditions on site are not. Currently reading for United States under IRC 2024 — pick a different market above and the figures re-cast accordingly.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Storage volume = surface area × reservoir depth × aggregate void ratio, the standard method for estimating the water storage capacity within a permeable pavement system's open-graded aggregate base

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Why does storage volume depend on the aggregate's void ratio?
The open-graded stone in the reservoir layer is not solid — it has open voids between the stones where water actually collects. Only that void fraction of the layer's total volume (surface area × depth) is available for stormwater storage, which is why the void ratio directly scales the storage volume.
Should I use a generic void ratio like 0.4 for my design?
Only as a preliminary estimate. Void ratio depends on the specific aggregate gradation used, and should be confirmed for your chosen open-graded base material — commonly tested per ASTM C29 — rather than assumed, since actual values for open-graded stone are typically in the 0.3–0.4 range but vary by source and gradation.
Does this include storage in the bedding or choker course layers?
No — this calculates storage in the main aggregate reservoir layer only, using the depth and void ratio you enter. Additional storage in bedding, choker, or sub-base layers with different gradations should be calculated separately and added if applicable.