How it shows up
Signs you need backflow testing
- Commercial tenant improvement requiring compliance sign-off
- Annual test notice received from the water purveyor
- New irrigation system, boiler or fire line commissioning
- A previous test failed and repair is required
The job itself
How backflow testing is done properly
Backflow Testing & Certification is handled by independent licensed plumbers in Illinois. This page covers what the work involves, what changes the price, and the Illinois code and permit rules that apply. Published ranges are on the separate backflow costs page. Locally, the biggest markets for it are Chicago, Aurora, Rockford. Requests for it often arrive alongside drain cleaning & clogged drains.
- The assembly type, size and serial number are recorded
- Water is temporarily isolated for the test sequence
- Differential pressure and check valve performance are measured
- Failed assemblies are rebuilt or replaced
- The report is filed with the water purveyor by the certified tester
Scope boundary
What a standard visit covers — and what is billed on top
The single biggest source of quote disputes is the boundary between these two columns. Get it written down before work starts.
| Normally included | Commonly billed on top |
|---|---|
| Restoring water service and confirming the assembly holds pressure | Purveyor filing and administration fees passed through to the owner |
| Filing the signed test report with the water purveyor | Vault pumping or confined-space entry to reach a buried assembly |
| Recording assembly make, model, size and serial number | Rebuild kits, springs and rubber parts after a failed test |
Price drivers
What drives backflow pricing in Illinois
- 01
Number and size of assemblies on the property
- 02
Whether a rebuild kit or full replacement is needed after a failure
- 03
Access and whether the assembly is in a vault
- 04
Purveyor filing fees
- 05
Whether after-hours isolation is required for a commercial tenant
Before you sign
Questions to ask before authorizing backflow testing
- 01
If the assembly fails, is a rebuild kit carried on the truck, or does a second visit become necessary?
- 02
How long will water be shut off during the test sequence, and can that be timed around occupancy or irrigation schedules?
- 03
Is the tester certified with the local water purveyor, because reports from uncertified testers are rejected and must be redone?
- 04
Who files the completed report with the purveyor, and by which annual deadline, since late filing can trigger penalties?
Coverage
Where backflow is requested in Illinois
Backflow is arranged statewide rather than from a per-city page: these are the largest markets, and each city page carries its own ZIP coverage, county and permit authority.
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Chicago
Cook County
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Aurora
Kane County
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Rockford
Winnebago County
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Joliet
Will County
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Naperville
DuPage County
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Peoria
Peoria County
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Springfield
Sangamon County
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Elgin
Kane County
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Waukegan
Lake County
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Champaign
Champaign County
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Cicero
Cook County
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Bloomington
Mclean County
Before anyone touches a pipe
Verify the license. It takes two minutes.
- Who licenses the work: Illinois Department of Public Health (IDPH) together with the local jurisdiction.
- Who pulls the permit: the licensed contractor, never the homeowner.
- What to ask for: the license number, the registered name behind it, and an insurance certificate issued to the property address.
Answers first
Backflow in Illinois — asked and answered
Why do I have to test my backflow preventer every year?
Because the checks inside it are mechanical and fail silently. Water purveyors mandate annual testing to protect the public supply from cross-contamination, and the requirement sits with the property owner.
What happens if I fail the test?
The assembly is rebuilt or replaced and retested. Purveyors typically give a short correction window, after which service can be interrupted — so do not sit on a failure notice.
Who can legally test my backflow assembly?
Only a tester holding the certification your water purveyor recognizes, using calibrated gauges. Ask for the certification number and the gauge calibration date.
Which areas does PlumberIllinois cover?
All of Illinois: the site lists every covered city with real ZIP codes, the county permit authority and nearby coverage, so requests route to a professional already working that area.
Is PlumberIllinois a plumbing company?
No. Independent licensed professionals perform and contract the work directly with you. PlumberIllinois routes the request and links every page to the official Illinois license register.
Does PlumberIllinois charge homeowners anything?
No. PlumberIllinois may be compensated by a partner when a homeowner connects with a professional through the site. That never changes what the contractor charges for the job.
Does calling create any obligation to hire?
None. A call or a callback request is a conversation, not a contract. Scope, timing and price are only agreed if you decide to proceed with the professional handling Illinois.
Are night and weekend calls handled differently in Illinois?
Requests route around the clock, but most contractors price after-hours work differently. Ask for the after-hours rate and a committed arrival window before agreeing to a dispatch.
Get connected
Backflow in Illinois
Say what is wrong and where in Illinois. An independent licensed professional calls you back; terms are agreed directly and the license can be checked before anything starts.
- Requests handled around the clock
- An independent licensed pro calls you back
- No obligation to hire
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Keep reading
Keep reading
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Cost guide
Backflow cost ranges in Illinois
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Services
All plumbing services
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Licensing
Illinois licensing and permits