Last updated Reviewed by our licensed Chicago master plumber team
Every food service establishment in Chicago is required by MWRD and city code to install and maintain a grease interceptor — no exceptions for restaurants, bars serving food, cafeterias, nursing homes, schools, commissaries, or catering kitchens. Plumbers 911 Chicago is the dedicated grease trap partner for hundreds of Chicago-area food service operations — from single-location diners in Logan Square to multi-unit restaurant groups across 245 cities. We handle scheduled pumping on strict compliance intervals (the 25% rule — pump before FOG reaches 25% of total depth), emergency overflow response when a trap backs up mid-service, new interceptor installation for new builds and renovations, repair and replacement of failed units, and MWRD manifest documentation filed with every service so your compliance paperwork is always current. We operate vacuum trucks 24/7, dispose of FOG at permitted rendering facilities, and provide the documentation health inspectors and MWRD ask for. Call 833-758-6911 for scheduled service or emergency response. Related: commercial plumbing, drain cleaning, sewer cleaning, hydro jetting, and sewer camera inspection.
Chicago MWRD Grease Trap Requirements
Chicago's Metropolitan Water Reclamation District (MWRD) and the city Department of Water Management both regulate grease traps. The rules are strict and enforced.
The 25% Rule (Most Important)
- Your trap or interceptor must be pumped before the combined thickness of floating FOG and settled solids reaches 25% of the total depth of the unit
- For most restaurants this means monthly or every 90 days depending on volume
- Inspectors will measure with a dipstick during unannounced visits
- Exceed 25% and you're out of compliance — fines start at $500 per violation
Required Documentation
Every pumping must be recorded on a MWRD-compliant manifest that includes:
- Date and time of service
- Volume pumped (gallons)
- Trap / interceptor ID and location
- Disposal facility name and permit number
- Driver and company name
- Signature of facility manager
You must keep 3 years of manifests on site and produce them on demand. We file each manifest with MWRD electronically on your behalf and retain the paperwork in your service account.
Proper Sizing (Per 2024 Chicago Code)
- Single restaurant dish sink: minimum 20 GPM / 40 lb grease-holding capacity (under-sink unit)
- Two-compartment prep kitchen: 25 – 50 GPM
- Full commercial kitchen: 500 – 2,000 gallon in-ground interceptor
- Chicago uses drainage fixture units (DFUs) formula — we calculate for every install
Non-Compliance Consequences
- $500 – $10,000+ fines per violation
- Forced temporary closure until compliance restored
- Liability for sewer backup damages caused by grease clog
- Insurance claim denial if FOG contributes to flooding
- Negative health-inspection scores (publicly posted)
Who Inspects
- MWRD inspectors: regular audits of FOG compliance
- Chicago Department of Water Management: permit and installation review
- Chicago Department of Public Health: routine restaurant inspections
We help prepare for all of them.
Grease Trap Pumping and Cleaning Service
What happens when we arrive for a scheduled or emergency pumping.
Our Pumping Process
- Locate and open the trap or interceptor access lid
- Measure existing conditions — FOG depth, solids depth, liquid level — recorded for the manifest
- Vacuum pump — remove 100% of the trap's contents (FOG, solids, and wastewater) into the truck
- Interior scraping — physically scrape the walls, baffles, and inlet/outlet fittings to remove hardened grease deposits (under-sink units especially)
- Inspection — check baffle integrity, flow direction, any cracks, and connections
- Rinse — flush with clean water to verify proper flow
- Lid replacement and documentation — replace lid securely, complete manifest, hand copy to manager
Common Pumping Intervals
| Establishment Type | Typical Interval |
|---|---|
| Coffee shop / light breakfast | 90 – 120 days |
| Small family restaurant | 60 – 90 days |
| Diner / full-service restaurant | 30 – 60 days |
| Fast food with fryers | 30 days (often more frequent) |
| Full commercial kitchen (hotels, caterers) | 30 days or less |
| Schools / nursing homes | 90 days (lower volume but required) |
Costs
- Under-sink trap (20 – 50 GPM): $225 – $475 per service
- In-ground interceptor (250 – 500 gal): $475 – $900 per service
- In-ground interceptor (750 – 1,500 gal): $875 – $1,400+ per service
- Large interceptor (2,000+ gal): $1,400 – $2,800+ per service
- Emergency service (overflow, mid-shift): $625 – $1,850 depending on scope and time
Service Contracts
Most restaurants benefit from standing service agreements:
- Fixed scheduled pumping at your required interval
- 15 – 25% discount vs. one-off pricing
- Priority emergency response (same-day guaranteed)
- Automatic manifest filing with MWRD
- Compliance reports monthly
Grease Trap and Interceptor Installation
New restaurant buildout? Renovation adding a fryer? Expansion? You likely need a new interceptor or upgrade.
Types We Install
Under-Sink Grease Trap (Small Kitchens):
- 20 – 50 GPM capacity
- Installed in the cabinet below dish sinks
- Cost: $650 – $2,400 installed
- Best for: Coffee shops, small diners, limited-menu restaurants, delis
In-Ground Grease Interceptor (Standard Restaurants):
- 500 – 2,000+ gallon capacity
- Typically outside in parking lot or alley
- Concrete or HDPE plastic construction
- Cost: $4,500 – $18,000+ installed (excavation dependent)
- Best for: Most full-service restaurants, bars serving food, commissaries
Hydromechanical Grease Interceptor (HGI):
- Compact indoor unit with higher GPM rating than traditional under-sink
- Typically 100 – 400 GPM
- Cost: $3,500 – $8,500 installed
- Best for: Space-constrained kitchens where in-ground isn't feasible
Automatic Grease Removal Unit (AGRU):
- Heats FOG and automatically skims it to a collection container
- Reduces pumping frequency by 60 – 80%
- Cost: $7,500 – $22,000+ installed
- Best for: High-volume kitchens where pumping costs exceed AGRU payback
Installation Process (In-Ground Interceptor)
- Sizing calculation per Chicago DFU formula based on your fixtures
- MWRD submittal and DOB plumbing permit application
- JULIE 811 utility locate (48-hour minimum)
- Excavation — typical hole is 6'×10'×6' deep for a 1,000-gallon interceptor
- Set the interceptor on crushed-stone base, leveled
- Connect inlet and outlet to kitchen drain and sewer main
- Backfill with granular fill in 6" lifts, compacted
- Concrete or asphalt restoration at surface
- MWRD inspection before first use
- Commissioning — full fill test, flow verification, access lid seating
Typical Installation Timeline
- Permit and submittal: 2 – 6 weeks (varies by MWRD review backlog)
- Excavation through inspection: 2 – 5 days
- Total project: 3 – 8 weeks from start to first use
Emergency Grease Trap Service
When a trap or interceptor overflows mid-service, the kitchen stops running and every minute costs revenue. We run 24/7 emergency vacuum trucks.
Common Emergency Scenarios
- Trap overflow during service — kitchen floor flooded with FOG and wastewater
- Sewer backup — grease has caused a blockage downstream
- Odor complaints from neighbors — overflowing trap venting odor
- Failed inspection — MWRD cited you, need pumping before re-inspection
- New ownership takeover — unknown history, need immediate compliance pumping
- Grease blockage in kitchen drain line — traced back to the trap
What We Bring
- Vacuum truck (1,500 – 4,500 gal capacity)
- High-pressure water for cleaning and line flushing
- Line camera for downstream inspection (if blockage suspected)
- Certified disposal manifest paperwork
Emergency Response Times
- Downtown / North Side: 45 – 90 minutes typical
- Suburbs within 20 miles: 60 – 120 minutes
- Extended metro (outer suburbs): 90 – 180 minutes
Preventing Future Emergencies
- Schedule standing service (90% of emergencies are preventable)
- Install AGRU or larger interceptor if your trap is sized too small
- Train kitchen staff on "never pour grease down the drain" protocols
- Add water-wise cleaning practices (cold water with dish soap scrapes better than hot water)
- Quarterly sewer camera inspection to catch buildup early
Frequently Asked Questions About Grease Trap Services
How often do I need to pump my grease trap in Chicago?
Per MWRD and Chicago code, you must pump before FOG reaches 25% of trap depth. In practice: coffee shops 90 – 120 days, small diners 60 – 90 days, full-service restaurants 30 – 60 days, fast food with fryers monthly or more. A service contract establishes the right interval for your volume — and we track and file documentation automatically.
How much does grease trap cleaning cost in Chicago?
Under-sink trap (20 – 50 GPM): $225 – $475 per service. Small in-ground interceptor (250 – 500 gal): $475 – $900. Mid-size (750 – 1,500 gal): $875 – $1,400. Large (2,000+ gal): $1,400 – $2,800+. Emergency / after-hours: $625 – $1,850. Service contracts reduce per-visit cost by 15 – 25%.
What size grease interceptor do I need for my restaurant?
Chicago uses a drainage fixture unit (DFU) calculation based on your kitchen fixtures (prep sinks, dish sinks, fryers, woks, mop sinks, etc.) and peak flow rate. Rough guide: coffee shop = 20 – 50 GPM under-sink; small diner = 250 – 500 gal in-ground; full restaurant = 750 – 1,500 gal in-ground; full commercial kitchen = 1,500 – 2,000+ gal. We calculate and submit the correct sizing as part of every installation quote.
What happens if my grease trap overflows during service?
Stop using the kitchen drains immediately (shut off dish machines, fryers, and prep sinks). Contain the overflow with absorbent pads or towels. Call us at 833-758-6911 — we run 24/7 emergency vacuum response. Do NOT attempt DIY cleanup — FOG is classified as commercial waste and must be disposed of at a permitted facility. We'll also document the event for your records and provide any reports required by MWRD or the health department.
What's the difference between a grease trap and a grease interceptor?
Grease trap (sometimes called a "hydromechanical" or "under-sink" trap) is a smaller unit (20 – 100 GPM) installed near the dish sink. Good for coffee shops and small kitchens. Grease interceptor is a larger in-ground unit (250 – 2,000+ gallons) that handles the entire kitchen's drain output. Required for most full-service restaurants. Chicago code sizes these based on your peak flow and fixture units.
Do I need a permit for a new grease interceptor in Chicago?
Yes — always. Installation requires a Chicago DOB plumbing permit AND MWRD approval. Installation sizing must meet current code based on your fixture count and flow rate. We handle the entire permit process: sizing calculation, submittal to MWRD for review, permit application, inspection coordination. Timeline: 2 – 6 weeks for approval, 2 – 5 days for installation once approved.
Can I clean my grease trap myself to save money?
No — and it's illegal. FOG is commercial waste that must be disposed of at a permitted rendering facility, and every pumping must be documented on an MWRD-compliant manifest. DIY cleaning leaves you with no disposal manifest (automatic violation), no disposal facility receipt (second violation), and no proof of proper cleaning for inspectors. Plus you'll have 50 – 1,000 gallons of FOG to get rid of. Hire a licensed vacuum service — it's not optional.
What are the fines for non-compliance with grease trap rules?
Fines vary by violation type: missed pumping $500 – $2,500; improper sizing $1,000 – $5,000; no manifest documentation $250 – $1,500 per missing record; FOG causing sewer backup $5,000 – $10,000+ plus damages. Repeat offenders face temporary business closure until compliance restored. Insurance may deny FOG-caused backup claims. Compliance is dramatically cheaper than fines.
Can an automatic grease removal unit (AGRU) reduce my pumping costs?
Yes, significantly — AGRUs automatically heat and skim FOG to a collection container, reducing pumping frequency by 60 – 80%. Payback period is typically 2 – 4 years for high-volume kitchens. Monthly pumping costs of $1,200+ often justify the $7,500 – $22,000 AGRU investment. Lower-volume operations usually don't see payback. We evaluate ROI as part of any installation consultation.