Cardinal Hill Subdivision, OK
Lead detected, under the action levels
Latest 90th-percentile lead: 0.41 ppb (monitoring period 2022-2024). 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.
About Cardinal Hill Subdivision
Cardinal Hill Subdivision serves about 475 people through 187 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Marshall County, Oklahoma. EPA system ID: OK2004539; phone on file: 580-564-7069. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
Against the period ending 2021 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Cardinal Hill Subdivision is 13.78 ppb across 3 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 0.41 ppb |
| 2021 | 0 (not detected) |
| 2018 | 13.78 ppb over 10 |
Where this result ranks
Of the 870 Oklahoma systems with a lead result, the median latest reading is 0.81 ppb; 6 are over 15 ppb right now and 66 have gone over at some point. Cardinal Hill Subdivision's 0.41 ppb sits at the 45th percentile in Oklahoma and the 42nd nationally (higher means more lead).
Neighbouring systems
7 other systems share Marshall County; 5 of them have a higher latest lead result than Cardinal Hill Subdivision. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Marshall County Rural Water District #2 | 17,587 | 1.1 ppb |
| Madill | 3,410 | 1.7 ppb |
| Kingston Pwa | 1,600 | 0.5 ppb |
| Oakland Pwa | 1,050 | 1.54 ppb |
| Oakview Water Corp | 925 | 2.4 ppb |
| Marshall County Rwd #1 | 468 | - |
| Texoma Hills | 212 | 0 (not detected) |
Next steps for Madill, OK
Test your own tap with a certified lab first-draw sample; Madill, OK 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 Cardinal Hill Subdivision 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. The lead result guide covers how utilities pick the homes they sample. The action level is dropping - the 10 ppb rule from 2027.