Best Septic Design Software: How to Choose

Short answer: the best septic design software is the one that knows your jurisdiction's rules, brings in the site data you'd otherwise collect by hand, does the sizing and hydraulics, and produces the drawings your reviewer accepts. Designers use five kinds of tools: general CAD (AutoCAD, Civil 3D), state-specific design programs, spreadsheets and agency forms, GIS, and browser-based septic design apps such as landplan.io. Many combine two or more.

We make landplan.io, so read this with that in mind. We've tried to describe every approach fairly, stick to what we could verify, and say where landplan.io is not the right fit.

What to look for in septic design software

Need	Questions to ask
Your rules	Does it apply your state's and county's flows, loading rates, separations and setbacks, or do you enter them? Who keeps them current?
Site data	Does it bring in parcels, elevation, soils, water features and flood zones, or do you import them?
Sizing	Does it size the tank and the absorption area from the bedrooms and the soil test? Can you see where each number came from?
Hydraulics	Does it handle pressure distribution, force mains, friction losses and pump selection?
System types	Does it cover the systems you design: trenches, chambers, mounds, LPP, drip, at-grade, treatment units, spray?
Drawings	Does it produce a site plan, cross section and hydraulic profile at scale, in a format your reviewer accepts?
Products and costs	Does it use real products and prices, and produce an estimate?
Interoperability	Can it import a survey (DXF, shapefile) and export to CAD or GPS?
Field work	Can you use it on a phone at the test pit? Import GPS points?
Review and teams	Can a reviewer or a colleague open the plan? Can a team share settings?
Cost and trial	What does it cost per seat, and can you try it on a real job first?

General CAD: AutoCAD and Civil 3D

Many septic designers draw in AutoCAD or a similar CAD program, and engineering firms often use Autodesk Civil 3D, which adds surfaces from survey data, grading, pipe networks and profiles.

Strengths:

• Complete control over the drawing, and the industry-standard file formats.
• Civil 3D's surfaces and profiles suit sites with full topographic surveys and large or commercial systems.
• Firms already have the licenses, the templates and trained staff.

Limits for septic work:

• Neither applies onsite wastewater rules. Sizing, loading rates and pump calculations are done separately, often in a spreadsheet, and kept in step with the drawing by hand.
• Site data (parcels, soils, contours) has to be found and brought in.
• Subscriptions and training are a real cost for a small design practice.

Best for: engineers and firms already working in CAD, large or commercial systems, and sites with full surveys.

State-specific septic design programs

Some states have had programs written for their own rules, often desktop software.

• Septic Planner (North Carolina). An NC State Extension page describes Septic Planner as software developed by the Pamlico County Health Department and LandPlot Research to design and document nitrification fields under North Carolina's rules, for conventional, low-pressure pipe, polystyrene aggregate, chamber and bed systems. The page says it calculates drainfield dimensions and pump requirements, prints permit exhibits, and exports a drawing to LandPlot's QuikPlat Pro. It describes a Windows program; check with LandPlot for the current version.
• BJSoftware (Pennsylvania). Listed in several software roundups as Pennsylvania on-lot design software covering systems such as sand mounds and at-grade beds. We couldn't find an official product page to confirm its current features, so ask the vendor or your sewage enforcement officer.
• Septic Edge. SEPTICEDGE is a registered trademark for computer software for planning on-site sewage facilities or septic systems, and it appears in software roundups. We couldn't confirm its current features or availability from an official source.

Strengths: written around one state's rules and forms, sometimes with the support of local reviewers. Familiar to those reviewers.

Limits: usually one state only, so a designer working across a state line needs another tool. Desktop programs may not bring in site data, and some are older; check what's maintained.

Best for: designers who work in one state where a well-supported program exists.

Spreadsheets and agency forms

Many designers size systems in their own spreadsheets, or in worksheets and forms published by their state or county. In Ontario, for example, municipalities publish Part 8 septic forms that capture the soil data, the daily design flow and the distribution layout (such as Oshawa's form).

Strengths: free or cheap, accepted by the reviewer who wrote the form, and fully under your control.

Limits: no drawing; numbers retyped from the field sheet to the spreadsheet to the drawing; easy to carry an error across; hard to share a template that stays current when the rules change.

Best for: checking a calculation, and simple systems where the form is the submittal.

GIS: QGIS and ArcGIS

GIS programs are excellent for site screening: parcels, soils, wetlands, flood zones and buffers on one map. Some counties publish their septic and parcel data as GIS services.

Limits: GIS is not a septic design tool. It doesn't size systems, run hydraulics or produce cross sections and profiles, and you build every layer and setting yourself.

Best for: site screening, many-lot planning and agencies managing records.

Manufacturer tools

Many product makers publish design manuals, sizing tables and pump selection tools for their own products. They are accurate for those products and often required by the product's state approval, but they cover only one brand.

Browser-based septic design: landplan.io

landplan.io (formerly NewSeptic) is septic design and land planning software that runs in the browser. Here is what it does, plainly:

• From an address. Type an address, parcel number or coordinates. The parcel lines, elevation contours (from public lidar, USGS 3DEP in the US and NRCan in Canada), the NRCS soil survey, water features, wells and FEMA flood zones load onto the map.
• Your rules. Designs follow the configuration for your state or province and county: flows, loading rates, separations, setbacks and the systems allowed. See which areas we cover on the data coverage page and the rules by state on septic rules by state.
• Smart design and Auto design. Smart design takes you through site, soil, system, house, spot, tanks, pipes and review, ranking the systems that fit. Auto design does the whole draft from an address and the bedrooms in about a minute, and says why it made each decision. Both draw ordinary map features you can edit by hand.
• System types. Trench, mound, LPP, drip, at-grade, cut and fill and proprietary large diameter pipe systems can be generated; Smart design places spray heads for spray systems, and lagoons and discharging systems are drawn with the map's tools. See Septic System Types.
• Calculations. Details shows the flow, soil, area, elevations, pressure network and pump, and where each number came from; Checks lists what doesn't meet the rules.
• Soil. State soil test forms, percolation readings, and a field log for the test pit, on a phone.
• Report PDF. Title, hydraulic profile, cross section, top view, site plan, dosing detail and calculations.
• Products and cost. Real products from distributors near the site, with prices and an estimate PDF with labor, fees and delivery. See the price index.
• Interoperability. Import shapefile, DXF, GPX and KML; export CSV points, shapefile, DXF, GPX and DWG; open maps in QGIS with an API key.
• Review and teams. Share a map link, send a report for plan review to an inspector, and run a team as an organization with roles and a shared price book. Health departments can receive reviews: plan review for health departments.
• Jobs. Verified designers can bid on homeowners' design requests. See Septic Design Jobs.

Where landplan.io is not the right fit:

• If your county's rules aren't configured yet, you'd be working from defaults: check the septic pages for your state first, and tell us what's missing.
• Large commercial or community systems that need full engineering drawings are better done in CAD; you can still export landplan.io's map to DXF or DWG as a start.
• It needs a connection to load site data. It works on a phone, but it isn't an offline desktop program.
• It drafts and calculates; a licensed professional still checks and signs the plan.

Pricing is on the pricing page, and the first week is free.

Which approach suits you

You are	A good fit
An engineering firm doing commercial systems	CAD (Civil 3D), with landplan.io for site screening and quick residential designs
A designer working in one state with a supported state program	That program, or landplan.io if you want site data and reports in one place
A designer or installer working across counties or states	A tool with each area's rules, such as landplan.io
A soil evaluator	A field log on a phone, with state forms
A health department	Plan review, a shared view of submitted designs, and records

Frequently asked questions

Is there free septic design software?

Agency worksheets and spreadsheets are free, and some state programs have been distributed by agencies. landplan.io has a free first week, so you can try it on a real address.

Can I use AutoCAD for septic design?

Yes. Many designers do, with the sizing done separately. AutoCAD draws; it doesn't apply septic rules.

Do health departments accept plans from landplan.io?

Health departments review the plan's content, not the software. landplan.io's report is laid out as a permit set (site plan, sections, profile, calculations), and a licensed professional signs it where your state requires.

What happened to NewSeptic?

NewSeptic is now landplan.io: the same company (NewSeptic, Inc.) and the same software, under a name that covers land planning beyond septic.

Can landplan.io import my survey?

Yes: a surveyor's DXF or shapefile, GPX and KML files, and GPS points. See Upload GIS Data.

Try it from an address

Create a free account, type an address you know, and press Auto design: you get a system that fits your county's rules, its report and its cost estimate, to compare with how you work today.