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City water profile

Washington water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Washington, District of Columbia.

Median indexed hardness

66PPM

57 indexed ZIPs

Range 65–69.8 PPM

State comparison
At state median
State hardness rank
#1 of 1
Matched utilities
1
Active health records
0

City summary

What the indexed records say

Washington has 57 published ZIP profiles across District Of Columbia County. The indexed median is 66 PPM, compared with 66 PPM across District of Columbia.

Among the 1 District of Columbiacities with an indexed median, Washington ranks #1from highest to lowest. Across all 57 state ZIP profiles, available estimates run from 65to 69.8 PPM.

The 65–69.8 PPM range shows how much the available ZIP estimates vary within the city label.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard57 ZIPs
Hard0 ZIPs
Very hard0 ZIPs

57 of 57 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
5.4 miles
Profiles with evidence
57/57

Confidence labels

High: 0Moderate: 57Low: 0

Observation window: Jan 4, 2016 to Jun 30, 2026.

ZIP directory

Water reports in Washington

Open a ZIP for site-level provenance and measurements.

ZIP code

20001

Moderately Hard

65.9 PPM

Nearest site
5.5 mi
Confidence
Moderate

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ZIP code

20002

Moderately Hard

65.7 PPM

Nearest site
7.4 mi
Confidence
Moderate

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ZIP code

20003

Moderately Hard

65.5 PPM

Nearest site
6.8 mi
Confidence
Moderate

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ZIP code

20004

Moderately Hard

65.9 PPM

Nearest site
5.4 mi
Confidence
Moderate

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ZIP code

20005

Moderately Hard

65.9 PPM

Nearest site
4.9 mi
Confidence
Moderate

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ZIP code

20006

Moderately Hard

67.6 PPM

Nearest site
4.6 mi
Confidence
Moderate

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ZIP code

20007

Moderately Hard

67.6 PPM

Nearest site
1.6 mi
Confidence
Moderate

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ZIP code

20008

Moderately Hard

67.7 PPM

Nearest site
3.1 mi
Confidence
Moderate

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ZIP code

20009

Moderately Hard

67.7 PPM

Nearest site
4.3 mi
Confidence
Moderate

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ZIP code

20010

Moderately Hard

67.7 PPM

Nearest site
4.6 mi
Confidence
Moderate

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ZIP code

20011

Moderately Hard

68.4 PPM

Nearest site
5.3 mi
Confidence
Moderate

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ZIP code

20012

Moderately Hard

69.8 PPM

Nearest site
5.8 mi
Confidence
Moderate

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ZIP code

20015

Moderately Hard

67.8 PPM

Nearest site
4.1 mi
Confidence
Moderate

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ZIP code

20016

Moderately Hard

67.6 PPM

Nearest site
1.5 mi
Confidence
Moderate

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ZIP code

20017

Moderately Hard

67.6 PPM

Nearest site
6.7 mi
Confidence
Moderate

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ZIP code

20018

Moderately Hard

65.9 PPM

Nearest site
7.7 mi
Confidence
Moderate

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ZIP code

20019

Moderately Hard

65.2 PPM

Nearest site
5.2 mi
Confidence
Moderate

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ZIP code

20020

Moderately Hard

65 PPM

Nearest site
5.6 mi
Confidence
Moderate

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ZIP code

20024

Moderately Hard

65.9 PPM

Nearest site
6.3 mi
Confidence
Moderate

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ZIP code

20032

Moderately Hard

65.7 PPM

Nearest site
7.2 mi
Confidence
Moderate

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ZIP code

20036

Moderately Hard

67.6 PPM

Nearest site
4.3 mi
Confidence
Moderate

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ZIP code

20037

Moderately Hard

66.8 PPM

Nearest site
4.3 mi
Confidence
Moderate

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ZIP code

20045

Moderately Hard

65.9 PPM

Nearest site
5.2 mi
Confidence
Moderate

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ZIP code

20052

Moderately Hard

67.6 PPM

Nearest site
4.3 mi
Confidence
Moderate

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ZIP code

20057

Moderately Hard

67.6 PPM

Nearest site
2.7 mi
Confidence
Moderate

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ZIP code

20059

Moderately Hard

66.8 PPM

Nearest site
5.2 mi
Confidence
Moderate

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ZIP code

20064

Moderately Hard

67.6 PPM

Nearest site
6.3 mi
Confidence
Moderate

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ZIP code

20204

Moderately Hard

65.5 PPM

Nearest site
6.3 mi
Confidence
Moderate

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ZIP code

20220

Moderately Hard

65.9 PPM

Nearest site
5 mi
Confidence
Moderate

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ZIP code

20230

Moderately Hard

65.9 PPM

Nearest site
5 mi
Confidence
Moderate

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ZIP code

20240

Moderately Hard

67.6 PPM

Nearest site
4.7 mi
Confidence
Moderate

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ZIP code

20245

Moderately Hard

67.6 PPM

Nearest site
4.6 mi
Confidence
Moderate

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ZIP code

20250

Moderately Hard

65.9 PPM

Nearest site
5.4 mi
Confidence
Moderate

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ZIP code

20260

Moderately Hard

65.9 PPM

Nearest site
5.9 mi
Confidence
Moderate

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ZIP code

20317

Moderately Hard

66.8 PPM

Nearest site
5.5 mi
Confidence
Moderate

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ZIP code

20319

Moderately Hard

65.5 PPM

Nearest site
6.9 mi
Confidence
Moderate

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ZIP code

20373

Moderately Hard

65.5 PPM

Nearest site
7.2 mi
Confidence
Moderate

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ZIP code

20388

Moderately Hard

65.2 PPM

Nearest site
6.6 mi
Confidence
Moderate

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ZIP code

20390

Moderately Hard

65.2 PPM

Nearest site
6.8 mi
Confidence
Moderate

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ZIP code

20408

Moderately Hard

65.9 PPM

Nearest site
5.7 mi
Confidence
Moderate

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ZIP code

20415

Moderately Hard

67.6 PPM

Nearest site
4.6 mi
Confidence
Moderate

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ZIP code

20418

Moderately Hard

66.8 PPM

Nearest site
4.5 mi
Confidence
Moderate

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ZIP code

20422

Moderately Hard

66.8 PPM

Nearest site
5.7 mi
Confidence
Moderate

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ZIP code

20427

Moderately Hard

67.6 PPM

Nearest site
4.2 mi
Confidence
Moderate

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ZIP code

20431

Moderately Hard

67.6 PPM

Nearest site
4.4 mi
Confidence
Moderate

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ZIP code

20510

Moderately Hard

65.9 PPM

Nearest site
6.4 mi
Confidence
Moderate

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ZIP code

20515

Moderately Hard

65.7 PPM

Nearest site
6.5 mi
Confidence
Moderate

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ZIP code

20520

Moderately Hard

67.6 PPM

Nearest site
4.4 mi
Confidence
Moderate

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ZIP code

20530

Moderately Hard

65.9 PPM

Nearest site
5.5 mi
Confidence
Moderate

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ZIP code

20535

Moderately Hard

65.9 PPM

Nearest site
5.5 mi
Confidence
Moderate

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ZIP code

20540

Moderately Hard

65.7 PPM

Nearest site
6.7 mi
Confidence
Moderate

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ZIP code

20542

Moderately Hard

67.7 PPM

Nearest site
4.8 mi
Confidence
Moderate

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ZIP code

20551

Moderately Hard

66.8 PPM

Nearest site
4.6 mi
Confidence
Moderate

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ZIP code

20560

Moderately Hard

65.9 PPM

Nearest site
5.5 mi
Confidence
Moderate

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ZIP code

20565

Moderately Hard

65.9 PPM

Nearest site
5.9 mi
Confidence
Moderate

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ZIP code

20566

Moderately Hard

67.6 PPM

Nearest site
4 mi
Confidence
Moderate

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ZIP code

20591

Moderately Hard

65.9 PPM

Nearest site
5.8 mi
Confidence
Moderate

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Public water systems

Utilities associated with this city

D.c. Water And Sewer Authority

PWSID DC0000002

Surface water
System population served
632,323
Last reported
May 11, 2026

A municipal system, in-state city, and served county all agree with this Census ZCTA.

Compliance history

What EPA records show

No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.

RecordSystemPeriodStatus
Revised Total Coliform RuleDC0000002Jan 1, 2023Resolved
Surface Water Treatment RuleDC0000002Jan 1, 2023Resolved
Revised Total Coliform RuleDC0000002Dec 1, 2022Resolved
Surface Water Treatment RuleDC0000002Dec 1, 2022Resolved

Practical next steps

Move from index to evidence

  1. 1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
  2. 2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
  3. 3. Test the tap when needed. Confirm health concerns or treatment sizing with the right method.

Questions people ask

About water in Washington

Is the water hard?

The indexed city median is 66 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.