Oil-Water Separator Sizing Guide

Match Your Compressed Air System CFM to the Right OWS Model

Selecting the correct oil-water separator isn’t guesswork—it’s a compliance decision. An undersized separator can’t treat your condensate volume fast enough, risking discharge above the EPA’s 15 ppm limit. An oversized unit wastes capital that could be deployed elsewhere.

This guide helps you size your OWS correctly the first time.

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Why Sizing Matters

EPA violations for improper condensate discharge can result in fines of $25,000 to $50,000 per day. Beyond the financial penalty, violations can trigger increased regulatory scrutiny, required remediation, and reputational damage with customers who require compliant suppliers.

  • Undersized separator: Condensate flows faster than the unit can process, causing discharge above 15 ppm—an EPA violation
  • Oversized separator: Equipment works correctly but you’ve overspent on capacity you don’t need
  • Properly sized separator: Compliant discharge, optimal capital allocation, and headroom for future expansion

OWS Sizing Table

Match your total compressed air system CFM to the appropriate Joruva OWS model:

Compressed Air System CFM Recommended OWS Model Service Interval
Up to 75 CFM OWS75 6,000 hours
76–150 CFM OWS150 6,000 hours
151–450 CFM OWS450 6,000 hours
451–1,000 CFM OWS1000 6,000 hours
1,001–2,000 CFM OWS2000 6,000 hours
2,001–3,500 CFM OWS3500 6,000 hours
3,501–7,000 CFM OWS7000 6,000 hours

All Joruva OWS models feature Reactis™ biological separation technology and are certified for <15 ppm discharge.

How to Calculate Your CFM

Your oil-water separator must handle the total condensate output from all compressors feeding into it. Here’s how to calculate:

  1. List all compressors connected to the separator
  2. Sum their CFM outputs at the operating pressure
  3. Add 20% buffer for future expansion and operational fluctuation
  4. Select the OWS model that covers your calculated total

Example: Multi-Compressor Facility

Your facility has:

  • 1× 25HP rotary screw compressor (100 CFM)
  • 1× 15HP rotary screw compressor (65 CFM)
  • 1× 7.5HP reciprocating compressor (28 CFM)

Total System CFM: 100 + 65 + 28 = 193 CFM
With 20% buffer: 193 × 1.2 = 232 CFM

Recommended Model: OWS450 (covers up to 450 CFM)

This provides headroom for future compressor additions while ensuring your condensate treatment stays compliant.

Why Joruva OWS Outperforms Competitors

Most oil-water separators require service every 4,000 hours. Joruva’s Reactis™ technology extends service intervals to 6,000 hours—50% longer than the industry standard. That’s fewer service calls, less downtime, and lower total cost of ownership.

Key Differentiators

  • Reactis™ biological separation technology: Probiotic-enhanced media biodegrades oils more effectively than passive filtration
  • 6,000-hour service life: 50% longer than competitors’ 4,000-hour standard
  • Certified <15 ppm discharge: Documentation ready for auditors
  • Compliance Partnership included: Audit-ready documentation, proactive service reminders, and pre-audit support

Multi-brand distributors sell you equipment and disappear. We stay with you through every inspection.

Frequently Asked Questions

How do I size an oil-water separator for my air compressor?

Add up the CFM output of all compressors feeding the separator. Select an OWS model rated for at least that total CFM. We recommend adding a 20% buffer for future expansion. For example, a 200 CFM system should use an OWS450 (rated to 450 CFM) rather than sizing to the minimum.

What happens if my oil-water separator is undersized?

An undersized separator can’t process condensate fast enough, causing oil concentrations in the discharge to exceed the EPA’s 15 ppm limit. This is a Clean Water Act violation that can result in fines of $25,000 to $50,000 per day, plus required remediation.

What is the EPA discharge limit for compressed air condensate?

The EPA requires that oil-in-water concentration in discharged condensate be below 15 parts per million (ppm). All Joruva OWS models are certified to achieve <15 ppm discharge when properly maintained.

How often do oil-water separators need service?

Industry-standard oil-water separators typically require service every 4,000 operating hours. Joruva OWS models using Reactis™ technology extend this to 6,000 hours—50% longer service intervals mean fewer service calls and lower maintenance costs.

Can one separator handle multiple compressors?

Yes. Size your separator based on the combined CFM output of all compressors feeding into it, plus a 20% buffer. A facility with three compressors totaling 200 CFM should use an OWS450 (rated to 450 CFM) to ensure adequate capacity and room for future expansion.

Not Sure Which Model Fits Your System?

Our team can review your compressed air configuration and recommend the right OWS model for your facility. Every Joruva purchase includes our Compliance Partnership—ongoing support to help you stay audit-ready.

Tell us about your compressed air system and we'll recommend the right separator.

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