Illinois lead water service lines: what landlords must know (2026)

1. Notices you (and your tenants) should get

• Lead line found. When a utility identifies a lead service line connected to a building, it must try to notify the building owner and all occupants within 15 days, or as soon as reasonably possible (415 ILCS 5/17.12(j)).
• Planned replacement. At least 45 days before a planned replacement, the utility must mail the owner a request for access and permission. If the owner does not respond within 15 days, the utility tries to post the request on the building entrance (415 ILCS 5/17.12(ii)).
• Before work starts. For planned work on lead lines or water mains with lead lines attached, the utility gives the owner and occupants written notice at least 14 days ahead, by mail or posted at the main entrance, and by email when it has an address. For a multi-unit building it can post at the main entrance and where mail is delivered (415 ILCS 5/17.12(jj)).
• What the notice says. A warning that the work may stir up lead sediment, tips like flushing lines and cleaning faucet aerators, and information on lead risks to young children and pregnant women (415 ILCS 5/17.12(jj)).

2. Owner duties that catch landlords

• No DIY partial replacements. Partial lead service line replacements are prohibited, with narrow exceptions such as emergency repairs (415 ILCS 5/17.12(ff)). If an owner plans to replace part of a lead line (or a galvanized line that is or was downstream of lead), the owner must notify the utility at least 45 days before starting (415 ILCS 5/17.12(gg)).
• Filters if you say no. If an emergency repair leaves a partial replacement and the owner of a nonresidential building or a rental property denies a complete replacement, the owner must install and maintain point-of-use filters certified to NSF/ANSI 53 and NSF/ANSI 42 for lead and particulate at every fixture used for drinking, food preparation or making baby formula, until the rest of the line is replaced (415 ILCS 5/17.12(ff)).
• Emergency repair by the owner. In an emergency repair, the owner of the building must provide certified filters (NSF/ANSI 53 and 42) for each kitchen area (415 ILCS 5/17.12(gg)).
• Waiver. If the utility can’t get approval to replace the line, it asks the owner to sign a waiver developed by IDPH; refusals or no response are reported to the Department (415 ILCS 5/17.12(ii)).
• Access for free replacements (new in 2026). As amended by P.A. 104-572 (effective July 10, 2026), a private property owner must allow the utility access to replace the private-side lead or galvanized-requiring-replacement line when the utility offers it at no cost. If the owner is unavailable or unwilling, any legal occupant may give consent and sign the access forms, and is held harmless for doing so (415 ILCS 5/17.12(qq)).

3. Naperville: 2026–2027 replacement cycle

The City of Naperville says it is replacing lead service lines one property at a time, the new copper line is free for homeowners, and affected owners will be contacted by mail and in person. Its posted timeline: property-by-property replacements starting mid-June 2026, active replacement June to November 2026, substantial completion anticipated mid-November 2026, and final surface restoration November 2026 to June 2027. The city also provides a water filter pitcher and testing (City of Naperville).

Check your address on the city’s Lead Service Line Map from that page. Naperville lead paint rules for landlords: Naperville page and Naperville landlord guide.

Landlord checklist (our suggestion)

1. Look up each building on your water utility’s posted service line inventory (utilities must post it or have the state post it, 415 ILCS 5/17.12(l)).
2. Answer utility letters fast; a 45-day request with no reply after 15 days gets posted on your door.
3. Say yes to free full replacements and coordinate access with tenants.
4. Don’t let a plumber replace only part of a lead line; notify the utility 45 days before any planned partial work.
5. If you decline a full replacement after an emergency repair, buy and keep up NSF/ANSI 53 and 42 certified filters at every drinking and cooking tap.
6. Keep copies of every utility notice and filter purchase with your lead records.

Our checklist suggestion for staying organized, not an official form.

Track lead paint disclosures, mitigation deadlines and records for every unit in one free place.

Illinois lead rules Naperville page

Does an Illinois landlord have to replace a lead water service line?

Illinois puts the replacement duty on the community water supply, which must replace all known lead service lines on a set timeline. Owners must not do partial replacements on their own and must give the utility 45 days’ notice before replacing part of a line (415 ILCS 5/17.12(v), (ff), (gg)).

Will my tenants be notified about a lead service line?

Yes. When a utility identifies a lead service line it must try to notify the building owner and all occupants within 15 days, and it must give owners and occupants written notice before planned replacement or main work (415 ILCS 5/17.12(j), (jj)).

What happens if I refuse a lead service line replacement on my rental?

The utility asks you to sign an IDPH waiver. If an emergency repair left a partial replacement and you deny a complete one on a rental property, you must install and maintain NSF/ANSI 53 and 42 certified filters at every fixture used for drinking, food preparation or baby formula (415 ILCS 5/17.12(ff), (ii)).

Can my tenant let the water utility in without me?

As amended effective July 10, 2026, if the owner is unavailable or unwilling, any legal occupant may consent to a no-cost replacement and sign the access forms, and is held harmless for doing so (415 ILCS 5/17.12(qq)).

Is Naperville replacing lead service lines in 2026?

Yes. The City of Naperville says it is replacing lead service lines property by property in its 2026–2027 cycle, the new copper line is free for homeowners, and substantial completion is anticipated in mid-November 2026.