The Suction Side Works Under Vacuum
When a pump draws water from a tank, borehole, river or pit, the hose is exposed to negative pressure. Atmospheric pressure pushes inward and can flatten a hose without enough structural support. A suction helix or steel-wire reinforced hose uses a rigid spiral to maintain the bore.
The suction line must also be airtight. A worn gasket, loose camlock or cracked fitting allows air into the line, so the pump may lose prime or deliver less water even though the hose body is strong enough.
The Discharge Side Carries Pressure and Flow
After the pump, the hose carries water to the field, tank, nozzle or drainage point. It must resist working pressure, surge and dragging while remaining practical to move and store. PVC layflat hose is a common choice because it rolls flat and uses container space efficiently.
Pressure rating, diameter and length must be considered together. A long discharge line creates more friction, and a hose that is too small can reduce flow even when the pump is powerful.
| Feature | Suction hose | Discharge hose |
|---|---|---|
| Main load | Vacuum and external crush | Internal pressure and flow |
| Typical structure | Rigid helix or steel-wire skeleton | Woven jacket, braided fibre or reinforced wall |
| Common product | PVC suction helix hose, steel-wire hose | PVC layflat, high-pressure layflat, fire hose |
| Where it sits | Water source to pump inlet | Pump outlet to field or delivery point |
| Key check | Airtight joints and vacuum rating | Working pressure, diameter and friction loss |
Choose by function
Why Layflat Hose Should Not Be Used for Suction
A standard layflat hose is designed to carry pressurised water after the pump. It has limited resistance to vacuum and can flatten or delaminate when used as a suction line. Even if it appears to work at first, the restriction can damage flow and shorten hose life.
If the application requires one hose for both suction and delivery, check that the product is explicitly rated for both duties. Do not assume that every hose described as a “water hose” is suction-rated.
A Reliable Pump Set Uses Both Hose Types
A practical irrigation or dewatering set usually combines a short suction hose, a pump and a longer layflat discharge line. Match the suction diameter to the pump inlet and the discharge diameter to the pump outlet. Then select pressure classes from the actual lift, run length and pump performance.
For mobile systems, specify couplings that two people can connect without special tools. For permanent systems, consider abrasion, UV exposure, chemical contact and the need to inspect or replace individual sections.
Products mentioned in this guide
Всасывающий ПВХ-шланг со спиральным каркасом
Жёсткая пластиковая спираль — устойчив к отрицательному давлению и истиранию
View productПВХ-шланг, армированный стальной спиралью
Спираль из стальной проволоки — устойчив к вакууму и смятию, прозрачная стенка
View productПлоский ПВХ-шланг
Полиэфирное плетение с ПВХ покрытием — для орошения и пожаротушения
View productFrequently asked questions
Can a suction hose also be used for discharge?
Many suction hoses can handle some positive pressure, but the rating must be confirmed for the specific product. Use a hose with both vacuum and pressure ratings when the line truly changes duty.
How do I know if my hose is collapsing under vacuum?
Look for flattening, a reduced water column, pump cavitation, loss of prime or visible distortion near the pump inlet. Check joints and gaskets for air leaks before blaming the hose.
Which hose should be longer, suction or discharge?
Usually the discharge line is longer because it reaches the field or delivery point. Keep the suction line as short and direct as practical to reduce lift losses and air-leak risk.