Measurements · Water Quality
TSS
Also known as total suspended solids, turbidity to tss
Total suspended solids.
What it is
What is TSS?
Total suspended solids (TSS) is the mass of solid particles suspended in water, reported in milligrams per liter: the sediment, organic debris, plankton, and fine matter that make water cloudy but do not dissolve. It is distinct from dissolved solids: TSS is what a filter would catch, while TDS is what passes through. As a true concentration it is a key measure of sediment pollution, erosion, and treatment performance, and it is the parameter most directly tied to how much material a river is carrying. TSS is closely linked to turbidity, which measures the optical effect of those same particles. Because turbidity is far easier to log continuously, TSS is often estimated from turbidity through a site-specific relationship rather than measured directly.
Because suspended sediment damages habitats and carries pollutants, TSS is central to river, stormwater, and discharge monitoring.
Health and operational effects
Suspended solids harm aquatic ecosystems by blocking light, smothering riverbeds and spawning gravels, and abrading and clogging the gills of fish and invertebrates. The particles also transport nutrients, metals, and pathogens attached to their surfaces, so a high TSS load delivers pollution as well as sediment, and when it settles it can blanket the bed and starve it of oxygen. Persistent high TSS signals erosion in the catchment, construction or agricultural runoff, or a failing treatment process.
How it is measured
How TSS Is Measured
The reference method for TSS is gravimetric (filtering a known volume of water and weighing the dried residue), which is precise but slow and cannot be done continuously in the field. For continuous monitoring, TSS is instead inferred from an optical turbidity sensor on a multiparameter sonde connected to a Thiamis gateway. A site-specific calibration relates turbidity in NTU to TSS in milligrams per liter, so the sonde reports a continuous estimate. Because the estimate relies on the turbidity sensor, it needs the same maintenance: the optical window must be kept clear of biofouling, bubbles, and debris (ideally with a wiper), and the sensor calibrated against standards to keep drift in check.
An instrument on Thiamis3
A third-party instrument connected to a Thiamis gateway, reporting into the same Environet account.
Placing TSS sensors
Because continuous TSS comes from the turbidity channel, the sonde is placed in-situ in well-mixed flow at a representative point, away from stagnant pockets where solids settle out and away from spots that trap debris. Continuous logging is essential because suspended-solids loads are driven by episodic events (storms, discharges, dredging) whose peaks pass quickly and dominate the total load, so a spot sample rarely captures them. Keeping the optical window clean and the turbidity-to-TSS relationship current, alongside regular calibration, is what keeps the estimated concentration trustworthy.
Every device and option that measures TSS 3
| Device / option | Type | Base platform | Measures |
|---|---|---|---|
 YSI · EXO1, EXO1S, EXO2… | Water Quality Sondes | Thiamis | |
 In-Situ · Level TROLL 300, Level TROLL 400, Level TROLL 500… | Water Quality Sondes | Thiamis | |
 Spectra Scientific · Spectra Litmus 6, Spectra Litmus 4 | Water Quality Sondes | Thiamis |
Where it is monitored
Solutions That Monitor TSS
Each one links to the solution page showing what that industry measures it for.
Water Quality Monitoring
Often addedRivers, lakes, drinking water, and stormwater
Article Library
Reading on TSS
Air Quality Near Data Centers: What Communities Should Know
Air quality near data centers: construction dust, diesel generator emissions, and noise, and how communities get independent monitoring data.
Data Center Air Quality Monitoring, Inside and Out
Data center air quality monitoring for operators: ISO 14644 cleanliness in the white space, construction dust, generator emissions, and perimeter noise.
Related
More in Water Quality
Questions
TSS FAQ
How is TSS different from TDS?
TSS is the mass of undissolved particles a filter would catch, while TDS is the mass of dissolved substances that pass through the filter. One describes cloudiness-causing sediment and debris; the other describes dissolved salts and minerals. They are measured and interpreted quite separately.
Can TSS be measured continuously?
Not directly. The laboratory method requires filtering and weighing a sample. In the field, TSS is estimated continuously from an optical turbidity sensor using a site-specific relationship between turbidity and suspended-solids concentration. This gives a real-time estimate that a wiper and regular calibration keep reliable.
Why does TSS matter?
Because suspended sediment blocks light, smothers riverbeds and spawning gravels, clogs fish gills, and carries attached nutrients, metals, and pathogens. High TSS therefore damages ecosystems and delivers pollution, and it is a regulated measure of how well treatment and stormwater controls are removing solids.
How do I monitor TSS?
Deploy a multiparameter sonde with an optical turbidity sensor, calibrated to a local turbidity-to-TSS relationship and connected to a Thiamis gateway, logging continuously through storm events. Use the configurator to pair a logger with a sonde covering TSS and turbidity alongside dissolved oxygen, conductivity, and temperature.
Monitor TSS on the Record
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