Mountain Valley Water System, WA
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (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. 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
Mountain Valley Water System serves about 126 people through 42 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Pierce County, Washington. EPA system ID: WA5373560. Ask the utility on your bill for your address in their service line inventory.
Mountain Valley Water System's lead record
That is down 14.6 ppb from 14.6 ppb in the period ending 2020. The highest 90th-percentile result EPA holds for Mountain Valley Water System is 14.6 ppb across 3 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 0 (not detected) |
| 2020 | 14.6 ppb over 10 |
| 2017 | 1.6 ppb |
Against other Washington systems
Of the 2,218 Washington systems with a lead result, the median latest reading is 1 ppb; 18 are over 15 ppb right now and 62 have gone over at some point. Mountain Valley Water System's reported as 0 (not detected) sits at the 18th percentile in Washington and the 11th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Other water systems in Pierce County
226 other systems share Pierce County; 151 of them have a higher latest lead result than Mountain Valley Water System. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Tacoma Water Division City Of | 446,245 | 0 (not detected) |
| Puyallup City Of | 94,520 | 2.7 ppb |
| Lakewood Water District | 82,425 | 1.1 ppb |
| Southwood | 64,155 | 1.6 ppb |
| Bonney Lake Water Department City | 43,371 | 2.4 ppb |
| Firgrove Mutual Inc | 36,168 | 2.9 ppb |
| Jblm Lewis | 35,414 | 0 (not detected) |
| Spanaway Water Company | 34,506 | 2.4 ppb |
| Parkland Light & Water Company | 33,775 | 2.4 ppb |
| Fife Dept Of Public Works | 29,091 | 2 ppb |
What to do in your house
Look up your address in Mountain Valley 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 Mountain Valley 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. The lead result guide covers how utilities pick the homes they sample. Small systems behave differently: why small systems go over more often.