Septic System LDP Calculator

CPP No-Rock™ LDP – Septic Field Sizing Tool (HTML)

CPP No-Rock™ LDP – Septic Field Sizing Tool

Design InputsUnits in parentheses

Customer Data

Customer name

Company (optional)

Street Address

City/Town

ZIP code

Cell phone

Demand (Q)

Bedrooms N (–)

q per bedroom (gpd/bed)

Use direct Q (gpd)

Design Parameters

LDP diameter (in)

LTAR (gpd/ft²)

W_equiv (ft²/ft)

s_oc (ft)

TW (in) (trench width)

Preset TW (in)

L_max per line (ft)

HC (in)

HS (in)

Slope S (%)

Af = Q/LTAR (ft²)

–

Lz = Af/W_equiv (ft)

–

n lines

–

Results

Click “Calculate”…

Disclaimer – LPD Septic Estimation Tool (Crumpler Pipe) This automated tool provides preliminary estimates only for Low-Pressure Dosing (LPD) septic systems using Crumpler Pipe. Results are approximate and not a final design. All system designs must be reviewed and approved by a licensed Professional Engineer or certified installer per local regulations. Final approval requires site-specific analysis, soil evaluation, and compliance with all federal, state, and local codes. This tool is based on design standards certified for use in North Carolina. Use outside NC must follow local authority guidelines. Use at your own risk. This tool does not replace professional judgment or permit requirements. The geometric layout of the septic system (pipes) must follow the spacing criteria recommended in the LDP Septic System Manual

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Scan the QR codes or click to open the catalog (PDF) and the interactive flipbook.

Reference image: CPP – Septic System LDP.

MSD = HC + HS; for a flat site, MSD = RSD.

Definition & Context
OC per NCAC 15A 18E (.0902/.0904): Conventional 6 ft; LDP 8″ → 5 ft, 10″ → 6 ft.
See NCDHHS – On-Site Water Protection for current regulation.

Tip: use “Preset TW” to comply with diameter options; the results also show summaries for all allowed TW values.

Sizing Report – CPP No-Rock™ LDP

1. Customer Data

2. Design Parameters & Demand

3. Results

4. Additional Summaries

— SINGLE TW SUMMARY (selected) —

— ALL TW SUMMARY (per datasheet) —

5. Tutorial Videos

Tutorial 1 – Introduction to CPP LDP: https://www.youtube.com/watch?v=ANxciaAxCMU
Tutorial 2 – Sizing Example: https://www.youtube.com/watch?v=Ok63vtd-3hs

6. Resources (QR – Catalog & Flipbook)

Catalog (PDF): https://www.cpp-pipe.com/wp-content/uploads/NO-Rock-Septic-QR_2025C-1.pdf

Flipbook: https://www.cpp-pipe.com/interactive-flipbook/

7. Equations Used

Af = Q / LTAR

Lz = Af / W_equiv

n = ceil( Lz / L_max ) ; L_line = Lz / n

TW(ft) = TW(in) / 12

W_total = (n − 1)·s_oc + TW(ft)

MSD = HC + HS

RSD = MSD + TW(in) · (S/100)

Notes: Allowed trench widths by diameter are limited to 8″ → 10/12/16 in and 10″ → 12/16/18 in. The report reflects the same validation rules used by the calculator.

8. Disclaimer – LPD Septic Estimation Tool (Crumpler Pipe)

This automated tool provides preliminary estimates only for Low-Pressure Dosing (LPD) septic systems using Crumpler Pipe. Results are approximate and not a final design.

All system designs must be reviewed and approved by a licensed Professional Engineer or certified installer per local regulations. Final approval requires site-specific analysis, soil evaluation, and compliance with all federal, state, and local codes.

This tool is based on design standards certified for use in North Carolina. Use outside NC must follow local authority guidelines.

Use at your own risk. This tool does not replace professional judgment or permit requirements.

The geometric layout of the septic system (pipes) must follow the spacing criteria recommended in the LDP Septic System Manual.