Mesa Water Department, WA
Lead detected, under the action levels
Latest 90th-percentile lead: 4.5 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.
Who runs the water here
Mesa Water Department serves about 495 people through 163 service connections, which makes it a very small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Franklin County, Washington. EPA system ID: WA5354100. Ask the utility on your bill for your address in their service line inventory.
Every lead result on file
That is up 3.5 ppb from 1 ppb in the period ending 2020. The highest 90th-percentile result EPA holds for Mesa Water Department is 4.5 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 4.5 ppb |
| 2020 | 1 ppb |
| 2017 | 4.2 ppb |
How Mesa Water Department compares
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. Mesa Water Department's 4.5 ppb sits at the 90th percentile in Washington and the 89th nationally (higher means more lead).
Neighbouring systems
30 other systems share Franklin County; 0 of them have a higher latest lead result than Mesa Water Department. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Pasco Water Department | 115,102 | 1.9 ppb |
| Connell City Of | 5,150 | 1 ppb |
| Basin City Water Sewer District | 1,740 | 0 (not detected) |
| White Bluff Water Association | 386 | 0.2 ppb |
| Ringold Domestic Water Corp | 340 | 0 (not detected) |
| West Mesa Domestic Water Assn | 316 | 0 (not detected) |
| Kahlotus City Of | 262 | 0 (not detected) |
| Cypress Country Estates | 253 | 0 (not detected) |
| Clark Addition Water System | 189 | 0 (not detected) |
| West 15 Domestic Water Assn | 150 | 1.3 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Mesa, WA 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 Mesa Water Department 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. What a 90th-percentile result does and does not tell you: how to read a lead result. Size matters more than most people expect: small vs large water systems.