Patterson Lake Water, WA
Lead detected, under the action levels
Latest 90th-percentile lead: 6.1 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 Patterson Lake Water
Patterson Lake Water serves about 79 people through 17 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Thurston County, Washington. EPA system ID: WA5366573. Ask the utility on your bill for your address in their service line inventory.
Patterson Lake Water's lead record
That is up 3.8 ppb from 2.3 ppb in the period ending 2021. The highest 90th-percentile result EPA holds for Patterson Lake Water is 6.1 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 6.1 ppb |
| 2021 | 2.3 ppb |
| 2018 | 1.5 ppb |
How Patterson Lake Water 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. Patterson Lake Water's 6.1 ppb sits at the 93rd percentile in Washington and the 94th nationally (higher means more lead).
Other water systems in Thurston County
195 other systems share Thurston County; 29 of them have a higher latest lead result than Patterson Lake Water. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Olympia City Of | 126,966 | 3.4 ppb |
| Lacey Water Department | 105,178 | 6 ppb |
| Tumwater City Of | 51,924 | 8 ppb |
| Yelm City Of | 17,355 | 1.9 ppb |
| Tanglewilde Thompson Place 600 | 7,900 | 2.8 ppb |
| Pattison 500 | 4,643 | 3.1 ppb |
| Grand Mound | 3,764 | 0 (not detected) |
| Tenino City Of | 3,336 | 9 ppb |
| Rainier Water Department | 3,103 | 3.4 ppb |
| Meadows 690 | 3,100 | 5.9 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Napavine, 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 Patterson Lake Water 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.