The tools

Two ways in, one shared brain.

Size it yourself, or just ask. Both run on the same verified engine, locked to Lowridge's approved design manuals — so the number you get is the number you submit.

One shared engine — the number you size and the answer you get stay locked to the same source of truth.

OSCAR onsite wastewater treatment and dispersal system
Lowridge Onsite Technologies, Inc.

OSCAR

On-Site Sand Coil Area Recharge
On-Site Technologies  ·  by Lowridge

Onsite wastewater treatment and dispersal in the industry's smallest footprint — meeting the highest treatment standard required by code, with no disinfection accessories. Serving Washington, Oregon, Idaho and Arizona.

  • Builds lots others can't — shallow soil, high water tables, tight setbacks.
  • Highest treatment standard in code — with no disinfection to buy, power, or maintain.
  • One complete engineered package — in the ground fast, with easy-to-follow instructions.
  • Invisible once planted — below-grade dispersal grows into the landscape.
240–100,000GPD design flows
Smallestfootprint in the industry
Zerodisinfection accessories
WA·OR·ID·AZstate-approved
Highest treatment standard, no disinfection Least soil required Complete system packages Custom-designed, one-stop shop
The OSCAR principle

Treat the water. Recharge the ground.

On-SiteSandCoilAreaRecharge
OSCAR

Wastewater disperses through coils on contour over a shallow sand bed — meeting the highest treatment standard in code, then returning clean water to the ground. The least soil, the smallest footprint, no disinfection.

Our products

Products that protect and conserve our water resources.

Lowridge provides the onsite wastewater industry with the products that protect and conserve our water resources — complete system packages that make installation quick and simple, with easy-to-follow instructions.

Infinite flexibility
FLAGSHIP PRODUCT

The OSCAR-XO2

Our primary product has daily design flows ranging from 240 gpd to 100,000 gpd, the industry's smallest footprint, requires the least amount of soil, and is capable of meeting the highest recognized treatment standard required by code — without any disinfection accessories.

240–100KGPD design flow
Smallestfootprint
Nodisinfection needed
DISPERSAL

OSCAR-II & OSCAR-III

Coil-based treatment and dispersal families sized to the governing state loading-rate code. OSCAR-III remains a single-family residential path only, using the same coil-on-contour footprint approach with a lower loading rate per coil.

View manuals ↗
XO2 DESIGN PATHS

Residential & commercial XO2

Single-family residential design flow can exceed 480 gpd and may go up to 1,500 gpd when supported by the residential design path. Multifamily is commercial and should use XO2-15/XO2-35 kit tables, headworks, piping and multi-zone drawings from the approved XO2 design manuals.

View source library ↗
RETROFIT ONLY

Legacy low-flow retrofit

Legacy low-flow questions are handled only as retrofit-to-XO2 guidance. Current product selection and sizing should use OSCAR-XO2 and the approved state manuals.

View retrofit materials ↗
Before: legacy low-flow system
Before
After: OSCAR-XO2, grassed in
After: invisible once planted
Pre-assembled headworks

Every kit ships ready to flow.

Every OSCAR-XO2 kit includes a pre-assembled headworks box — flow meter, disc filter, pressure gauges, and solenoid zone valves, all plumbed and tested before it leaves Lowridge. No field assembly and no guesswork.

OSCAR-XO2 pre-assembled headworks box with the dosing flow path marked in red
The real pre-assembled box — dosing flow marked in red.
OSCAR-XO2 reverse-flush headworks — flow meter, disc filter, pressure gauges, and solenoid zone valves
The reverse-flush headworks — pre-assembled and tested.
+ How the dosing works, and the numbers behind it

The flow

  1. Effluent is pumped from the tank into the box.
  2. Through the flow meter, which totals the dose volume.
  3. Through the disc filter, so the small coil emitters do not clog.
  4. Past the pressure gauge, confirming dosing pressure.
  5. Into the supply manifold feeding the solenoid zone valves S1 to S5.
  6. One valve opens at a time, so only that zone is dosed.
  7. End of cycle, the lines flush to tank, scouring solids and drain-back water.

The math

Each OS-50 coil is 50 emitters × 0.42 gph = 21 gph = 0.35 gpm (an OS-100 coil is 0.70 gpm). For one zone:

  • Dosing flow = coils × 0.35 gpm
  • Flush flow = laterals × 1.6 gpm
  • Minimum pump flow = dosing flow + flush flow

Because the zones run one at a time, the pump is sized off the largest single zone, not all of them added together.

Head: friction loss = L × (min flow ÷ K)1.85, with K = 47 for 1″ pipe and 97 for 1.25″. TDH = friction + elevation, and it must stay at or under 50 ft.

Worked example — a 14-coil zone, 7 laterals, 1″ pipe, 130 ft run, 37 ft lift

  • Dosing flow = 14 × 0.35 = 4.9 gpm
  • Flush flow = 7 × 1.6 = 11.2 gpm
  • Minimum flow = 4.9 + 11.2 = 16.1 gpm
  • Friction = 130 × (16.1 ÷ 47)1.85 = 17.9 ft
  • TDH = 17.9 + 37 = 54.9 ft, just over 50, so bump to 1.25″ pipe or shorten the run.
Why OSCAR

The most efficient products and methods of wastewater treatment.

It is the mission of Lowridge to offer the most efficient products and methods of wastewater treatment — to protect our environment and to ensure the future of our water supply.

“Sustainability begins with economic viability. It ends with no negative environmental impacts. Lowridge products do both.”

Shallow soil & limited areaDesigned for sites other systems can't serve — some lots can only be developed with an OSCAR system.
Quick, simple installationComplete system packages with easy-to-follow instructions get systems in the ground fast.
Invisible once plantedInstalled below the surface — the drainfield grows lawn, shrubs and native plants and disappears into the landscape.

“Sustainability begins with economic viability — and ends with no negative environmental impact.

The mission of Lowridge Onsite Technologies
Approved Where You Build

Reviewed, listed, and permitted across the West.

Tap your state for approved products, manuals & drawings, distributors and certified professionals.

Manuals & Drawings

Everything for your state.

Choose your state to see approved products, manuals & drawings, distributors, certified professionals and training.

Some lots could only be developed because of an OSCAR system.

240 to 100,000 GPD · the industry's smallest footprint
Resources

Specs, drawings & design aids.

Browse all materials from oscaronsite.com ▾ open
Get started

Let's design your system.

Start with Ask OSCAR — most questions are answered in seconds. A rep only steps in when you're ready, so you skip the phone tag.

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Jump to your state's manuals, distributors and certified professionals.

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Size it

Designers & engineers: run a preliminary, to-the-manual sizing in the OSCAR Calculator.

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Connect

Professional project support for designers, regulators, distributors and project teams.

Contact form ↗ public Lowridge line (877) 476-8823
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Ask OSCAR mobile app

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The same role-aware OSCAR guidance, source-library lookup, sizing support, products, manuals and resources — packaged as a polished iPhone app, now available on the App Store.

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