Trillium Water System, AZ
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2026-2026). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. The latest 90th-percentile result was reported as 0 (not detected at the lab's limit). That says the sampled homes were low, not that your home has no lead service line. Check your utility's service line inventory for your address.
Who runs the water here
Trillium Water System serves about 1,100 people through 1,100 service connections, which makes it a small system under EPA's size classes. It is privately owned and draws groundwater, in Maricopa County, Arizona. EPA system ID: AZ0407773; phone on file: 623-349-6145. They can tell you what your service line is made of and whether they pay to replace it.
Lead results over time
The highest 90th-percentile result EPA holds for Trillium Water System is 0 ppb across 1 monitoring period, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 0 (not detected) |
How Trillium Water System compares
Of the 730 Arizona systems with a lead result, the median latest reading is 0 ppb; 9 are over 15 ppb right now and 58 have gone over at some point. Trillium Water System's reported as 0 (not detected) sits at the 45th percentile in Arizona and the 27th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Neighbouring systems
99 other systems share Maricopa County; 24 of them have a higher latest lead result than Trillium Water System. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Phoenix City Of | 1,695,000 | 2.74 ppb |
| Mesa City Of | 466,000 | 5.01 ppb |
| Gilbert, Town Of | 247,600 | 0 (not detected) |
| Chandler City Of | 247,328 | 1.4 ppb |
| Scottsdale City Of | 241,361 | 2.3 ppb |
| Glendale City Of | 234,766 | 2.11 ppb |
| Peoria City Of | 187,676 | 0 (not detected) |
| Tempe City Of | 165,000 | 4.4 ppb |
| Epcor - Agua Fria | 128,040 | 0 (not detected) |
| Avondale City Of | 96,130 | 0 (not detected) |
Your move
Look up your address in Trillium Water System's service line inventory. If it says lead, galvanized or unknown, test your tap. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Trillium Water System 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. Small systems behave differently: why small systems go over more often.