Rib Mountain Water Utility, WI
Lead detected, under the action levels
Latest 90th-percentile lead: 2.4 ppb (monitoring period 2023-2023). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
Who runs the water here
Rib Mountain Water Utility serves about 6,398 people through 2,416 service connections, which makes it a medium-sized system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Marathon County, Wisconsin. EPA system ID: WI7370660. Ask the utility on your bill for your address in their service line inventory.
Lead results over time
That is down 1.1 ppb from 3.5 ppb in the period ending 2020. The highest 90th-percentile result EPA holds for Rib Mountain Water Utility is 6.1 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 2.4 ppb |
| 2020 | 3.5 ppb |
| 2017 | 6.1 ppb |
Where this result ranks
Of the 947 Wisconsin systems with a lead result, the median latest reading is 1.33 ppb; 6 are over 15 ppb right now and 71 have gone over at some point. Rib Mountain Water Utility's 2.4 ppb sits at the 68th percentile in Wisconsin and the 77th nationally (higher means more lead).
Nearby utilities
22 other systems share Marathon County; 9 of them have a higher latest lead result than Rib Mountain Water Utility. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Wausau Waterworks | 39,994 | 5.8 ppb |
| Weston Municipal Utilities | 16,000 | 0.75 ppb |
| Kronenwetter Water & Sewer Utility | 6,931 | 0.76 ppb |
| Mosinee Waterworks | 3,406 | 2.2 ppb |
| Rothschild Waterworks | 3,190 | 7.3 ppb |
| Abbotsford Waterworks | 2,502 | 3.5 ppb |
| Schofield Waterworks | 2,205 | 0 (not detected) |
| Spencer Waterworks | 1,848 | 0.8 ppb |
| Colby Waterworks | 1,829 | 0.95 ppb |
| Marathon City Waterworks | 1,695 | 0.36 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Wausau, WI may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Rib Mountain Water Utility whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. Why sampled homes are the worst-case ones is in the guide to reading the number. Size matters more than most people expect: small vs large water systems.