Drinking Water Testing in a Laboratory: Parameters, Sampling, and Cost

If you need drinking water tested in a laboratory — for a new well, a house recently connected to the network, an apartment building with old plumbing, preparing powdered formula for a baby, or obtaining authorization for a guesthouse — the steps that matter are the same regardless of the reason: choose the package of parameters that suits your situation, collect the sample exactly as the laboratory requires, check before paying that the laboratory is genuinely accredited for those parameters, and then know how to read the report you receive. The final cost depends largely on how many parameters you request and how complex the microbiological testing is, not on a single rate that you can easily compare between two laboratories.

• The parameters you request depend on your actual situation — a well, the network, old plumbing, a baby, or authorization — not on a generic “complete” package.
• The physicochemical sample and the microbiological sample are collected differently, and a sampling error can invalidate the result or produce a false positive.
• An accreditation certificate must be checked directly for its status, expiry date, and scope, not simply because it appears on the laboratory’s website.
• The report compares each measured value with the admissible value for that parameter at the time of sampling; “compliant” is not a general verdict that remains valid indefinitely.

What you are actually testing before calling the laboratory

The quality of drinking water in Romania is currently regulated by Ordinance No. 7/2023, which entered into force on January 28, 2023, transposes Directive (EU) 2020/2184, and took over the area previously regulated by Law No. 458/2002 (source: infocons.ro). Even a report issued by an accredited laboratory in the summer of 2023 already lists its reference values as “in accordance with G.O. No. 7/28.01.2023,” rather than under the old law (source: Compania Apa Brașov). What matters to you is that the parameters you can request fall into three broad groups, and a good result in one group says nothing about the other two.

The basic physicochemical group covers pH, conductivity, turbidity, ammonium, nitrites, nitrates, iron, manganese, hardness, and the oxidation index (potassium permanganate consumption) — parameters that mainly show how the water has been affected along its path through the soil or the plumbing, not whether it is microbiologically safe. The microbiological group includes Escherichia coli, intestinal enterococci, coliform bacteria, and colony counts at 22°C and 37°C; for water that may be affected by surface water, Clostridium perfringens is also included. The third group concerns metals with an explicitly defined alert threshold: current regulations require the identification and replacement of lead components in distribution systems (source: infocons.ro — drinking water quality standards), which is why lead remains a frequently requested parameter alongside arsenic, especially in old plumbing. For general background on what can actually end up in tap water in Europe, before ordering a particular package, you can read the guide to what tap water in Europe contains.

Choose the right package for your situation

A laboratory that sells its own packages has a commercial reason to recommend the most comprehensive option, regardless of what you actually need. Your real situation determines which groups of parameters matter and which you can leave out without unnecessary risk.

Table: situation → parameters to request

Your situation	What to request	Why
New or untested well or borehole	Full physicochemical testing and full microbiological testing, including Clostridium perfringens if the source may be affected by surface water	The source is not monitored by any operator, so no group of parameters can be assumed to be “probably fine”
New house connected to the network	Residual chlorine, hardness, iron and manganese if the internal plumbing is old, plus basic microbiological testing	The public network is already monitored by the operator, but your own plumbing, from the meter to the tap, is not
Old apartment building with old pipes	Lead, iron, colour, and turbidity, plus microbiological testing	Old internal plumbing is the main reason lead has become a parameter that must be checked explicitly
Baby (preparing powdered formula)	Nitrates, nitrites, hardness, and microbiological testing	Nitrates and nitrites are especially relevant for infants, and a clean physicochemical and microbiological baseline matters before anything else
Guesthouse or business seeking authorization	The complete package required by the authority, plus the required retesting frequency	Authorization leaves no room for choice; the parameters and retesting schedule are set by the authority issuing the approval

How to collect a water sample correctly

For physicochemical testing, laboratories generally require a clean polyethylene or polypropylene container, first rinsed with a little water from the relevant tap, then filled completely, without air bubbles, after running the water continuously at a steady flow for at least two minutes, without turning off the tap during this period (source: Apa Canal — sample collection procedure). For microbiological testing, the rules are almost entirely different: the container must be sterile, with sterilization validity usually limited to a maximum of 21 days; it should be filled to about 80% of its capacity, without being rinsed beforehand, and care must be taken not to touch the mouth of the bottle with your hand or the tap while collecting the sample.

The difference matters because a clean bottle from home cannot replace a sterile container: any trace of detergent or any contact with the mouth of the bottle can affect a microbiological result, either masking actual contamination or producing a false positive. For the same reason, sending a microbiological sample by courier without a controlled cold chain throughout the entire journey poses a real risk to the quality of the result, not just an overlooked formality — bacteria can multiply or die in the container before the sample reaches the laboratory. Each laboratory has its own exact flushing time and required volume for each type of sample, so the guidance above describes typical practice, while the exact instructions from the laboratory you choose are what matter. Label the sample with the date, time, and collection location, keep it at 5±3°C, and take it to the laboratory, usually within 24 hours of collection.

Where to get the test: the public health directorate or a private laboratory, and how to check accreditation

The county Public Health Directorate and accredited private laboratories do not, in fact, solve the same problem. The Public Health Directorate officially monitors public sources and intervenes primarily from a public health perspective, while an accredited private laboratory responds to an individual request, usually with more flexible turnaround times for you as a person or business that needs a report issued in its name.

An accreditation certificate is not just a logo on a website. RENAR, the national accreditation authority, provides an advanced search of accredited bodies, including the laboratory’s name, location, certificate status and number, and issue and expiry dates (source: RENAR — search for accredited conformity assessment bodies). Before paying, check there whether the certificate is active and unexpired, rather than relying solely on the laboratory’s claim. One more detail worth checking separately: a valid certificate under SR EN ISO/IEC 17025 does not automatically cover every possible parameter, because each laboratory has its own scope of accreditation, listed in the certificate’s annex — and your specific parameter, whether lead or a particular microbiological method, must be explicitly included in that scope (source: infocons.ro — drinking water quality standards).

How to read the test report

A real test report generally follows the same row-by-row structure: the parameter, unit of measurement, measured value, admissible value (MAC), and the test method used — for example, SR EN ISO 9308-1:2015 for E. coli and coliforms, or SR EN ISO 7899-2:2002 for enterococci, with a separate note for non-accredited tests (source: Compania Apa Brașov — test report). “Compliant” strictly means that the measured value for that specific parameter falls within the MAC — a typical conclusion on a report might read, for example, “the water sample tested is compliant and falls within the permitted limits” — and it is not a general, long-term verdict on all the water from that source (source: Compania de Apă Târgoviște-Dâmbovița — microbiological test report).

A concrete example is more helpful than an abstract description: if you see 0 CFU/100 mL for coliforms, E. coli, and enterococci, that parameter is compliant; if nitrates or lead exceed the MAC, that parameter is marked non-compliant, while the rest of the report remains valid for the parameters that fell within the limits. When a single parameter is non-compliant, the usual next step is to repeat the sampling to rule out a collection error, followed by isolating the source — your own internal plumbing or the public network — and, if the problem comes from the network, notifying the distributor or the Public Health Directorate, not simply changing laboratories.

What affects the cost of testing

The number of parameters requested is the first factor: each parameter has its own accredited test method, with its own consumables and laboratory time, so a package with ten parameters naturally costs more than one with three. Microbiological testing usually costs more than basic physicochemical testing because it involves several days of incubation, a sterile container with limited validity, and stricter handling from collection through to reading the results. The collection and transport arrangements matter too: if a laboratory sampler comes to your home rather than you bringing the sample in yourself, the logistics of the cold chain change, and this is reflected in the price. A laboratory accredited by RENAR for the relevant parameter also incurs compliance costs — audits and maintaining certification — that an unaccredited laboratory does not, which partly explains why prices vary from one provider to another even for packages that appear identical.

Laboratory vs. home water tester: they are not the same thing

A home TDS, pH, or chlorine tester gives you a quick, useful indication for routine checks, but it does not produce an accredited report that is valid for authorization or microbiological diagnosis. Microbiological testing, in particular, cannot be approximated with a home tester: it requires controlled incubation and an accredited laboratory to confirm or rule out the presence of bacteria, not an instant chemical reaction. If you first want to understand what home testers actually show and when you need the additional step of laboratory testing, the guide to home water testers draws that distinction clearly.

If your report shows nitrate or TDS values above what you expect in water that has already been treated by the network, while the other parameters are fine, this is practically the only situation in this guide where it is worth considering an additional treatment solution: the manufacturer of the Hydrion Purity RO600 system states that its reverse osmosis membrane is designed to reduce dissolved solids, heavy metals, and nitrates in network water, and that its display shows TDS in real time for each filtered glass of water — a manufacturer’s claim, not an independent laboratory certificate for your specific case. The guide to what TDS in water actually means explains in detail what this kind of reading measures and why the number alone does not tell you everything about water safety.

Microbiological non-compliance, on the other hand, is not resolved by reverse osmosis, but by disinfection or treatment where the water enters the house; the whole-house water filtration guide covers exactly this type of intervention, for situations where the result shows a bacterial problem, not dissolved minerals.