DMR FAQs on Sampling
When will the change from 3 to 5 years be effective?
The change of the data retention period from 3 years to 5 years will occur when the Proposed Part 750 Regulations are adopted. At the current time we are unsure of when this will happen. A mass mailing to all SPDES Permittees will be sent out informing permittees of the change at that time.
Does it matter if the sampling day does not start at midnight (noon - noon)?
The start of the sampling day does not need to start at midnight, but must be consistent. This may need to approved by the Regional Office.
From 7AM - 7AM (24 composite), which "day" do you use for flow?
With composite sampling, the sample day is the day you took the sampler out. This is the convention used by both New York State and USEPA.
Can we use data from samples split with regulatory agencies on our DMR? Why would one choose to split a sample?
When a Permittee splits samples with a regulatory agency, the data cannot be used on the DMR. Cases where a permittee may choose to split samples, include QA/QC, or comparing the analysis of one lab with that of another.
If samples are split with DEC, should we make a note that the sample was split?
This is not necessary.
What if 2 labs have very different results?
The results must be averaged (see page 16 of manual) and reported on the DMR accordingly. However, an investigation should be made to ensure the results are valid.
If a fecal sample does not get to the lab on time and the measurement is really high (because of this), and we sample again the next day and that sample is fine, what do we do? Do we report both? How?
Do not use the 1st number in your reporting, since it is not a valid sample. Attach an explanation and follow the rules on page 13 of the DMR Manual.
If something changed at the WWTP and the data is coming up Too Numerous To Count (TNTC) should the facility be warning the lab that there was an upset, etc?
Yes, this is a good idea. By keeping open communication with the lab, the lab will know that they might need to perform additional dilutions on a sample.
If we do extra sampling because of a violation, do we need to report these values?
Yes. If these samples were taken according to the sampling procedures specified in 40 CFR Part 136, the values need to be reported on the DMR.
What do you mean by "extra sampling"?
Extra sampling is sampling that is in addition to the frequency that is specified in the SPDES permit. The permittee may decide to sample and analyze more frequently than is required by the permit. If these samples were taken according to the sampling procedures specified in 40 CFR Part 136, the values must be used in calculations for reporting on the DMR.
Do we have to report process control sampling?
If samples are taken according to the SPDES Regulations, (see numbered list, section 2.3) then they must be reported. Sampling which does not follow the regulations should not be reported.
Does a 24-hour composite need to run for the full 24 hours to be valid? If we do not have a full 24-hour composite, do we need to report this as invalid?
Yes, the 24 hour composite must run for the full 24 hours, to be considered a valid sample. A 24-hour composite which is not complete (does not contain samples for all 24 hours) is an invalid sample.
Can we have more information on the sampling plan?
The sampling plan is currently not in the regulations, but we will be recommending it. A DEC workgroup will make a model sampling plan (similar in concept to the model sewer use) and distribute it to permittees when we are ready to start accepting sampling plans.
Do we treat TNTC and greater than both as invalid samples?
Yes, use the valid data in the calculation and then add the greater than symbol to the Sample Measurement. The permittee must also attach a Report of Non-Compliance Form.
What happens if we collect a second 30 day average sample, when we usually only sample once per month?
In this case, you would average the two values and report this average as your 30-day average. You would also need to specify in the frequency of analysis that you sampled twice and you should explain in the comments area that you collected an additional sample and why.
Does the flow have to be from the same time as the sample for a parameter?
The flow used for calculation of mass loading is the average flow for the day the sampling was done.
Our quarterly metal lab submits data as "undetected". What do we do?
If the lab reports "undetected" instead of <###, the permittee should call the lab, explain that they need the actual value of the MDL rather than the word undetected. The lab has the information and should readily provide it, either on the report or as an addendum.