Porter Mountain Dwid, AZ
Lead detected, under the action levels
Latest 90th-percentile lead: 0.49 ppb (monitoring period 2021-2023). 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.
Porter Mountain Dwid at a glance
Porter Mountain Dwid serves about 322 people through 140 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Navajo County, Arizona. EPA system ID: AZ0409024; phone on file: 520-977-9439. They can tell you what your service line is made of and whether they pay to replace it.
Lead results over time
Against the period ending 2020 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Porter Mountain Dwid is 4.07 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 0.49 ppb |
| 2020 | 0 (not detected) |
| 2017 | 4.07 ppb |
Where this result ranks
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. Porter Mountain Dwid's 0.49 ppb sits at the 70th percentile in Arizona and the 43rd nationally (higher means more lead).
Nearby utilities
39 other systems share Navajo County; 15 of them have a higher latest lead result than Porter Mountain Dwid. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| City Of Show Low | 17,139 | 0 (not detected) |
| Arizona Water Co - Overgaard | 13,797 | 0 (not detected) |
| Arizona Water Co - Lakeside | 12,191 | 7.8 ppb |
| Winslow City Of | 9,789 | 0 (not detected) |
| Snowflake Town Of | 5,590 | 1.7 ppb |
| Ponderosa Dwid | 5,375 | 0 (not detected) |
| Holbrook City Of | 4,833 | 0 (not detected) |
| Town Of Taylor | 4,190 | 0 (not detected) |
| Arizona Water Co - Pinetop Lakes | 3,558 | 0 (not detected) |
| Pinetop Water Community Facilities Dist | 3,250 | 10 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Lakeside, AZ 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 Porter Mountain Dwid 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. Systems that went over once often dip back under; here is what that means.