Grotto Water Association, WA
Lead detected, under the action levels
Latest 90th-percentile lead: 2.1 ppb (monitoring period 2017-2019). 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 Grotto Water Association
Grotto Water Association serves about 36 people through 26 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: WA5330050. Ask the utility on your bill for your address in their service line inventory.
Grotto Water Association's lead record
That is down 1.4 ppb from 3.5 ppb in the period ending 2016. The highest 90th-percentile result EPA holds for Grotto Water Association is 3.5 ppb across 2 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2019 | 2.1 ppb |
| 2016 | 3.5 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. Grotto Water Association's 2.1 ppb sits at the 70th percentile in Washington and the 74th nationally (higher means more lead).
Nearby utilities
153 other systems share King County; 32 of them have a higher latest lead result than Grotto Water Association. 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 |
What to do in your house
Test your own tap with a certified lab first-draw sample; Skykomish, 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 Grotto Water Association whether it covers that cost before hiring anyone - many utilities now do. Its latest copper 90th percentile is 1500 ppb (copper action level 1,300 ppb).
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.