Mount Si Mobile Home Estates, WA
Lead detected, under the action levels
Latest 90th-percentile lead: 4.3 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 Mount Si Mobile Home Estates
Mount Si Mobile Home Estates serves about 200 people through 89 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in King County, Washington. EPA system ID: WA5356560. Ask the utility on your bill for your address in their service line inventory.
Mount Si Mobile Home Estates's lead record
That is up 3.3 ppb from 1 ppb in the period ending 2020. The highest 90th-percentile result EPA holds for Mount Si Mobile Home Estates is 4.3 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 4.3 ppb |
| 2020 | 1 ppb |
| 2017 | 1 ppb |
Where this result ranks
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. Mount Si Mobile Home Estates's 4.3 ppb sits at the 89th percentile in Washington and the 89th nationally (higher means more lead).
Neighbouring systems
153 other systems share King County; 13 of them have a higher latest lead result than Mount Si Mobile Home Estates. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Seattle Public Utilities | 1,161,961 | 1.6 ppb |
| Bellevue City Of | 321,349 | - |
| Kent Water Department | 166,421 | 0 (not detected) |
| Redmond Water System City Of | 163,335 | 2 ppb |
| Lakehaven Water And Sewer District | 148,809 | 3.3 ppb |
| Renton City Of | 108,091 | 1.9 ppb |
| Auburn City Of | 107,655 | 2.2 ppb |
| Highline Water District | 100,170 | 1.4 ppb |
| Northshore Utility District | 99,789 | - |
| Sammamish Plateau Water & Sewer | 79,362 | 1.7 ppb |
Your move
Test your own tap with a certified lab first-draw sample; North Bend, 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 Mount Si Mobile Home Estates 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.