Every year the City of Newark publishes a report describing what is in its drinking water. It is free, it is public, and it is the only document in this conversation that contains measured figures rather than opinions.
It is also written to satisfy a federal reporting rule, which is why it reads like a compliance form rather than something meant for you.
This is how to get through it in ten minutes, and what to ignore.
Why this post does not print the numbers
The figures change every year, and a plumber's blog quoting a stale hardness result is exactly the sort of second-hand number this post is arguing against. Read the current report. It is on the City's water quality reports page, and Public Works will help you find it on (302) 366-7000.
First: is this even your report?
A water quality report covers one public water system. Before you read anything in it, confirm it is yours.
- You get a City of Newark water bill. The City's report is yours.
- You are outside the city limits but on public water. Your supplier may be a different utility with its own report. The name is on your bill.
- You are on a private well. There is no report. Nobody tests your water but you, and nothing below applies — skip to the well section at the end.
That last case is more common around the edges of the 19711 ZIP than people expect, and it changes the whole picture. Private wells are covered separately in well water testing in New Castle County.
The five parts of any water quality report
They all follow the same structure, because the structure is prescribed.
1. Where the water comes from
A short description of the source — surface water, groundwater, or a blend — and usually a note about a source water assessment.
Worth reading once. It tells you whether your water starts as a reservoir, a creek, or wells, and that determines which contaminants are even plausible.
2. The detection table
The large table that occupies most of the document, and the part people bounce off. Each row is one substance, and the columns are always roughly these:
| Column | What it is | Read it? |
|---|---|---|
| Contaminant | The substance tested for | Yes |
| MCL | The enforceable legal limit | Yes |
| MCLG | The health goal, not a limit | Context only |
| Level detected | What was actually measured | Yes |
| Range | Lowest and highest of all samples | Yes — see below |
| Violation | Yes or No | Read this first |
| Likely source | Standard boilerplate | Rarely useful |
Read the violation column first. If every row says No, the system met every enforceable standard for the year. That is the headline, and it takes fifteen seconds to establish.
Then read the range, not the average. An average sits comfortably under a limit while individual samples brush against it. The range tells you how much the water varies across the year and across the distribution network, which is precisely what an average is designed to smooth away.
3. The definitions box
Small print, usually at the end, and it decodes everything above.
| Term | Meaning |
|---|---|
| MCL | Maximum Contaminant Level — the enforceable limit |
| MCLG | Maximum Contaminant Level Goal — a health target with a safety margin, sometimes zero |
| AL | Action Level — the concentration that triggers required steps by the utility |
| MRDL | Maximum Residual Disinfectant Level — for chlorine and similar |
| ppm / mg/L | Parts per million. Identical units. |
| ppb | Parts per billion. A thousand times smaller than ppm. |
| ND | Not detected at the laboratory's reporting limit |
| NTU | Turbidity — cloudiness, which is a treatment performance measure |
The ppm-versus-ppb distinction causes real confusion. A result in ppb is a thousandfold smaller number than the same result in ppm, and comparing one against a limit expressed in the other manufactures alarm out of nothing. Check the unit on every row before you react to it.
4. Lead and copper — reported differently on purpose
Lead and copper get their own treatment in the report, and it is the part most worth understanding.
They are not measured at the treatment plant. They are measured at customers' taps, because lead and copper enter water from plumbing rather than from the source. A utility can treat water so it is less corrosive; it cannot change the pipe running under your front garden.
So instead of an MCL there is an action level, and instead of an average there is a 90th percentile — the value below which 90% of samples fell. Exceeding it does not mean the water is unsafe at every tap. It obliges the utility to act: corrosion control, public education, and in some cases accelerated service line replacement.
The federal rules here changed in October 2024, lowering the lead action level alongside a replacement deadline and a requirement for suppliers to keep a service line inventory. What that means for a Delaware homeowner — including how to check whether your own line is lead, using a coin and a fridge magnet — is in lead service lines in Delaware.
5. Violations and special notices
If the system had a violation, it must be described here in plain language, along with what was done about it. A report with nothing in this section is a report with nothing to report.
Hardness: the number everyone asks about, that the report may not regulate
Here is the part that surprises people.
Hardness is not a health contaminant and has no enforceable federal limit. It is dissolved calcium and magnesium. It scales kettles, spots glassware, and shortens water heater life at high concentrations, but it is an aesthetic and economic question rather than a safety one.
It may appear in a secondary or unregulated-parameters table rather than the main one. It may take a phone call to Public Works to obtain at all. And it is still the single figure the entire water treatment sales industry is built on.
Two things let you interpret it properly.
The conversion. Reports state hardness in mg/L. Softener companies talk in grains per gallon.
1 grain per gallon is about 17.1 mg/L
So 85 mg/L is roughly 5 gpg. 171 mg/L is 10 gpg.
The scale. The classification used by the US Geological Survey:
| Description | mg/L | Grains per gallon |
|---|---|---|
| Soft | 0–60 | 0–3.5 |
| Moderately hard | 61–120 | 3.5–7 |
| Hard | 121–180 | 7–10.5 |
| Very hard | Over 180 | Over 10.5 |
City of Newark supply generally sits in the moderately hard band, which is why the Newark area page says scale here is kinder than in genuinely hard-water regions. Check the current figure yourself rather than trusting that sentence — including ours.
Softening is conventionally worth considering above roughly 7 grains per gallon. Below about 3.5 it is very hard to justify. Between the two it is a judgement about your own appliances and your own tolerance for spotted glasses, and deciding no is an entirely reasonable outcome.
Spotting a sales script
Water treatment is sold hard in this area. The report is the fastest way to test a claim.
| The claim | What to check |
|---|---|
| "Your water tested very hard." | Ask for the number, in mg/L or gpg, then compare it against the report and the table above. |
| "There is chlorine in your water." | There is, deliberately — it is the disinfectant keeping the mains safe. The report lists the residual against a maximum. |
| A dramatic precipitate demonstration on your worktop | These reactions are easy to produce in ordinary safe water. A laboratory result is evidence; a kitchen-table demonstration is theatre. |
| "This will fix your low pressure." | Treatment does not raise pressure. Restriction, a failing regulator or old galvanized causes that — see low water pressure. |
| "We are working with the city." | The city does not sell or endorse treatment equipment. Call Public Works on (302) 366-7000 and ask. |
A genuine recommendation names a measured figure, states the threshold it exceeds, and survives you checking both. Most do not get past the first step.
What the report cannot tell you
It stops at the property line. Everything past the main — your service line, your internal pipework, your water heater — is invisible to it.
Which means a perfect report is entirely compatible with brown water at your own tap, because galvanized supply pipe in a pre-1960 house corrodes internally regardless of what arrives at the kerb. A metallic taste, blue-green staining in a basin, or discolouration on one tap and not another are all house-side symptoms, and no treatment system addresses the cause.
If you are on a well
No report exists, no agency tests your water, and nothing above applies.
You are your own water utility, which means annual testing is the only thing standing between you and finding out the slow way. Bacteria and nitrate every year at minimum, plus the panel appropriate to this area. That is covered in well water testing in New Castle County, and the equipment side on well pumps and water treatment.
The upside: on a well, treatment decisions get made against your own laboratory results. That is a far better basis than a doorstep conversation.
In short
Find the current report on the City's website, or ask Public Works on (302) 366-7000. Confirm it covers your supplier.
Read the violation column first — all No means every enforceable standard was met that year. Then read the range rather than the average, because the average is designed to smooth away the variation you are trying to see. Check the unit on every row: ppb is a thousand times smaller than ppm.
Lead and copper are reported as a 90th percentile against an action level, not an average against a limit, because they come from plumbing rather than from the source.
Hardness has no enforceable limit and may not be in the main table at all. One grain per gallon is about 17.1 mg/L, softening is conventionally worth it above about 7 gpg, and Newark city supply is generally moderately hard.
And the report describes the water arriving at your property, not the pipes carrying it once it is there. That part is on you — and it is the part we actually work on.
Related questions
The City of Newark publishes it at newarkde.gov under Water Quality Reports, with an archive going back years. If you would rather have a paper copy, or you cannot find the current year, Public Works will point you to it on (302) 366-7000.
It goes by several names — Consumer Confidence Report, CCR, or annual water quality report. They are the same document. Under federal rules a community water system has to produce one each year and make it available to its customers, normally by the first of July.
City of Newark supply is generally described as moderately hard — comfortably below the hard-water regions of the country, and in most homes not a reason to buy treatment. But do not take that from us, or from a softener company. Take it from the current report, which prints the measured figure.
The one conversion you need: one grain per gallon is about 17.1 mg/L of hardness. If the report lists 100 mg/L, that is roughly 5.8 grains. Softening is conventionally considered worthwhile above about 7 grains per gallon, and rarely worth the cost below about 3.5.
MCL is the Maximum Contaminant Level — the legal limit a water system must stay under, set with treatment feasibility and cost taken into account. It is enforceable.
MCLG is the Maximum Contaminant Level Goal — the level at which no known health effect is expected, with a margin of safety. It is a health target rather than a limit, and for some contaminants it is set at zero. A result above the MCLG but below the MCL is normal and is not a violation. The column to read is the one headed Violation.
No, and this is the limit worth understanding. The report describes water as it leaves treatment and travels through the public mains. It says nothing about the service line into your property or the plumbing inside it.
Lead and copper are the exception, because those samples are taken at customers' taps rather than at the plant — which is exactly why they are reported as a 90th percentile rather than an average. Even then the sample set is a few dozen homes, not yours.