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Solving Drainage Issues

Bulgaria sadly falls way behind most EU countries in terms of drainage facilities. Drainage problems will not always manifest themselves immediately; rainwater will slowly erode the fabric of your house and problems may not become apparent until damp patches starts to appear. Failure to tackle your drainage issues can result in costly remedial measures, which could have been avoided through diligent planning in the first instance.

Many people fail to take note of the land their property sits on. It is vital that you observe the landscape surrounding your plot.

If your house is built on a slope or incline, rainwater will run off from higher ground and engulf or maybe even flood portions of your house. If your home is adjacent to or traversed by a stream, it may overflow during periods of heavy rainfall. If your home is located in one of the country's flood plains e.g. in the Danube area, adequate drainage should be your first priority.

If you do not know the area well, it is wise to talk with your neighbours to determine if there have been any instances of high water or an excessive surplus of water in periods of extensive rainfall.

Many houses are built on soil instead of solid rock. Soil types vary from region to region and even within a 5-acre area. You need to determine if the soil is stable, especially if you intend to build on a hillside. Some soils do not absorb water very well and this could present big problems when building your septic tank.

The Septic Tank

Septic tank is an alien concept to all of us who have been used to flushing the loo and leaving the rest to the council! Bulgaria does not have a national waste management. It is left to the individual property owners to take responsible for all waste and water flushed through their household drainage pipes. It is therefore essential that you ensure your property has an adequate sized underground septic tank to hold all of your waste.

There is since 2009 only one waste seperating and disposal plant located in a village near to Plovdiv, and plans have started in 2010 for a further 55 regional waste collecting and processing plants. However by 2014, the Bulgarian government will have to comply with EU regulations in the development and construction of waste and water treatment plants nationwide.

A septic tank is a watertight box usually made of pre-cast concrete, concrete blocks, or reinforced fibreglass, which lies below the ground. Access is via a metal hatch above ground. When household waste enters the septic tank several things occur: Lighter-than-water organic solid material floats to the surface and forms a layer of what is commonly called "scum". Bacteria in the septic tank biologically convert this material to liquid. Inorganic or inert solid materials and the by-products of bacterial digestion sink to the bottom of the tank and form a layer commonly known as "sludge". Only clear water should exist between the scum and sludge layers. It is this clear water that should overflow into the soil absorption area.

You need to contact the local water authorities to empty it on a regular basis. The frequency with which it needs emptying will depend on the size of the tank and the amount of use. You must be careful not to pour strong chemicals into your domestic water system as this can damage the pipes and kill all of the good bacteria, which breaks down the waste. Bleach, many household cleaners, antibacterial soap, disinfectants and antibiotics will weaken the good bacteria. Strong household substances such as paint stripper and Jeyes fluid will not only damage the good bacteria, but also any plants and grass surrounding your tank.

Gutters and Down Pipes

In heavy rain, a lot of rain falls onto the roof of your house and it is important to allow it to drain away from the house through a reliable gutter system. Gutters should be 100 mm to 112 mm in order to catch the rainfall effectively. The rain then flows into a down pipe, which should be 68-75 mm in diameter. Guttering and down pipes are available in UPVC and in aluminium in Bulgaria.

In most Western European countries, one the rainwater had flowed from the roof into the guttering and down pipe; it would pour into a gulley, which would take the water off into the underground drainage system. However, the lack of drainage in Bulgaria means that you need to consider various alternatives.


At the bottom of the down pipe, a collar can be fitted to point the water away from your property. Many Bulgarian builders neglect to add this vital piece of drainage equipment and failure to do so will result in water seeping into the walls and foundations of your house. This method is adequate, but not the best option. In addition, you must be certain that once the rain has exited the collar it does not pool in close vicinity to your house. It must drain away from the property in order to be effective.

A better, but more costly alternative is to run all down pipes to a system of gullies and then to use more pipes to run the water into your septic tank.

Water shortages frequently occur in Bulgarian villages throughout summer. Fitting a water butt to a down pipe to collect rain water is an excellent way of collecting water for times of draught and contributes towards conservation.

Drainage Trenches

Another solution to drainage issues is to build a French drain around your property. This is an in-ground trench that captures groundwater. This form of hidden piping can trap water before it enters your house. You can use the French drain to collect ground water and divert it to a low spot on the land, away from your house.

Building a French drain is relatively simple: dig a trench 15 - 30 cm wide and 15 - 30 cm deep around your house. Line the trench with 10 cm of washed gravel in the bottom of the trench. Then install a 10 cm perforated drain pipe on the bed of gravel. Cover the trench with another 10 cm layer of washed gravel. Place a 10 cm layer of straw on top of this layer of gravel. The straw protects the lower gravel and the drain pipe from being choked with silt or sediment from the soil. Finish the trench by filling it with washed gravel to within 2.5 cm of the top and then cover with soil.

Filter fabrics to line the sides of the trench or to cover the pipe are not recommended because they are designed to stop the movement of the silt. If the fabric gets clogged with silt, then water cannot find its way into the trench or the pipe and all of your hard work has been wasted.

French trenches need not be confined to the area around your house. They can be used to drain water from your garden or drive too.